Statistics Questions and Answers May 30, 2018

The following stem-and-leaf plot represents the test scores for 26 students in a class on their most recent test. Use the data provided to find the quartiles. Test Scores by Student Stem Leaves 6 1 1 2 3 4 6 7 9 7 1 2 3 4 6 7 9 9 8 1 1 2 5 9 2 3 4 7 8 8 Key: 6|1=61 Step 1 of 3 : Find the second quartile.

Both Mr. Byrd and Mrs. Byrd are employed. During 2019, Mr. Byrd had opened a restaurant and had business income of $11000. Mr. Byrd also had net employment income of $51000, after deducting $9500 of employment deductions. He also had $7,000 of interest income. Ms. Byrd had gross employment income of $82000, which included taxable benefits of

The following shows the distribution of final exam scores in a large introductory psychology class. The proportion of the total area under the curve is given for two segments. Order the scores 45, 60, 70, 72, and 85 from most frequent to least frequent. (b) What is the percentile of a score of 60? (c) What proportion of the sample scored below 70?

Two classes of pre-calculus students took an exam to place them into either Advance Placement (AP) or regular calculus the following year. Given the following data, can you reject the null hypotheses that, as groups these classes are equally prepared (or not) for AP calculus? Conduct the relevant hypothesis test to show your conclusion.

Toronto drivers have been going to small towns in Ontario (Canada) to take the drivers road test, rather than taking the test in Toronto, because the pass rate in the small towns is 90%, which is much higher than the pass rate in Toronto. Suppose that every day, 100 people independently take the test in one of these small towns. a) What is the

2. On this scale, a reading of zero corresponds to the correct fill height. Fifteen samples of size n-10 have been analyzed, and the fill heights are shown below. Sample Number 1.0 2.5 1.3 2.0 0.5 0.5 0.0 1.0 -1.0 1.0 -1.5 x_{6} 2 x_{4} -1.0 1.0 -1.0 0.0 -1.3 -1.0 -1.0 x_{13} 0.0 1.5 0.0 1.5 1.0 -1.0 0.5 1.5 1.0 -2.0 0.0 -2.0 x_{2} 0.5 -1.0 -1.0

A random sample of 250 observations is taken from population A, which has 30% of its population living in poverty: pA 5 .3. A second random sample of size 350 is taken independently taken from population B, which has 15% of its population living in poverty: pB 5 .15. a. What are the mean and standard deviation of the difference in the sample

Using Technology to Generate Normal Quantile Plots. In Exercises 13-16, use the data from the indicated exercise in this section. Use software (such as Statdisk, Minitab, Excel, or StatCrunch) or a TI-83/84 Plus calculator to generate a normal quantile plot. Then determine whether the data come from a normally distributed population. Red 0.889

The U.S. Bureau of Labor and Statistics reported that a person between the ages of 18 and 34 has had an average of 9.2 jobs. To see if this average is correct, a researcher selected a random sample of 8 workers between the ages of 18 and 34 and asked how many different places they had worked. The results were as follows: 8 12 15 6 1 9 13 2 At a =

Finding Critical Values and Confidence Intervals. In Exercises 5-8, use the given information to find the number of degrees of freedom, the critical values x? and x*, and the confidence interval estimate of o. The samples are from Appendix B and it is reasonable to assume that a simple random sample has been selected from a population with a

Finding Confidence Intervals. In Exercises 9-16, assume that each sample is a simple random sample obtained from a population with a normal distribution. Body Temperature Data Set 5 "Body Temperatures" in Appendix B includes a sample of 106 body temperatures having a mean of 98.20F and a standard deviation of 0.62F (for day 2 at 12 AM). Construct

Finding Confidence Intervals. In Exercises 9-16, assume that each sample is a simple random sample obtained from a population with a normal distribution. Professor Evaluation Scores Listed below are student evaluation scores of professors from Data Set 28 "Course Evaluations" in Appendix B. Construct a 95% confidence interval estimate of o for

What is the formula for Bouley's coefficient of skewness?

a) Which algorithm does Facebook use for face verification and how does it work(2 Marks) b) Youve won a 2milliondollar worth lottery We all get such spam messages. How can Al be used to detect and filter out such spam messages (3 Marks) c) Highlight the advantages of using humans over modern computers to accomplish a task (2 Marks) d) Explain the

Determine the magnitude of the resultant force and its direction measured counterclockwise from the positive x axis

An information technology (IT) provider of cloud backup and restore solutions for small to midsize businesses wants to study the consequences of ransomware attacks. A random sample of 50 small to midsized companies in the United States that have experienced a ransomware attack reveals the following: Time spent dealing with and containing a

You and several friends are about to prepare a lasagna dinner. The tasks to be performed, their immediate predecessors, and their estimated durations are as follows: Task Task Description Predecessors Time estimate (in minutes) te 2 to tm tp A Slice the mozzarella -- 4 5 6 B Mix eggs and ricotta cheese -- 5 6 8 C Cut up onions and mushrooms _ 6 7

A manufacturer of television sets is interested in the effect on tube conductivity of four different types of coating for color picture tube. The following conductivity data are obtained

A survey conducted by the Northwestern University Lindquist-Endicott Report asked 320 companies about the procedures they use in hiring. Only 54% of the responding companies review the applicants college transcript as part of the hiring process, and only 44% consider faculty references. Assume that these percentages are true for the population of

Compare the result of (a) through (d) with those of Burger King in Problem 5.16 and Wendy's in Example 5.4 on page 247.

A sociologist claims that children ages 1214 spent less time sleeping in 1981 than children ages 1214 do today. A study was conducted in 1981 to find the time that children ages 1214 spent sleeping on weekdays. The results (in hours per weekday) are shown below. Assume the population standard deviation is 0.5 hour.

The table below shows the number of cars (in millions) sold in the United States for various years and the percent of those cars manufactured by GM.Year Cars Sold (millions) Percent GM Year Cars Sold (millions) Percent GM1950 6.0 50.2 1980 11.5 44.01955 7.8 50.4 1985 15.4 40.11960 7.3 44.0 1990 13.5 36.01965 10.3 49.9 1995 15.5 31.71970 10.1 39.5

How much money do people spend on graduation gifts? In 2007, a federation surveyed 2815 consumers who reported that they bought one or more graduation gifts that year. The sample was selected in a way designed to produce a sample representative of adult Americans who purchased graduation gifts in 2007. For this sample, the mean amount spent per

10-18. An article in Fire Technology investigated two dif- ferent foam expanding agents that can be used in the nozzles of fire-fighting spray equipment. A random sample of five ob- servations with an aqueous film-forming foam (AFFF) had a sample mean of 4.7 and a standard deviation of 0.6. A random sample of five observations with alcohol-type

The average weekly income of information is private industry is $777. If the standard deviation is $77, what is the probability that a random sample of 50 information workers will earn on average more than $800 per week? Do we need to assume anormal distribution ? Explain

The following data are provided for two samples drawn from independent populations: W = 545, n1 = 25, and n2 = 25. Suppose the distribution of W is approximately normal. a. Calculate the mean and the standard deviation of the distribution of W. b. Specify the competing hypotheses to determine whether the median of Population 1 differs from the

A dean must distribute salary raises to her faculty for next year. She has decided that the mean raise is to be $2000, the standard deviation of raises is to be $400, and the distribution is to be normal. She will attempt to distribute these raises based on merit, meaning that people whose performance is better will get higher raises. You may use

A survey of the number of cell phone calls made by a sample of Verizon subscribers last week revealed the following information (refer attachment) . Develop a stem-and-leaf chart. How many calls did a typical subscriber make? What were the maximum and the minimum number of calls made?

Poll Results in the Media USA Today provided results from a survey of 1144 Americans who were asked if they approve of Brett Kavanaugh as the choice for Supreme Court justice. 51% of the respondents said that they did approve, and the margin of error was-given as plus or minus 3.5 percentage points. What important element of the survey was omitted?

Margin of Error For the poll described in Exercise 1, describe what is meant by the statement that "the margin of error was given as +3.5 percentage points."

Poll Results in the Media USA Today provided results from a survey of 1144 Americans who were asked if they approve of Brett Kavanaugh as the choice for Supreme Court justice. 51% of the respondents said that they did approve, and the margin of error was-given as plus or minus 3.5 percentage points. Notation For the poll described in Exercise 1,

Confidence Levels Given specific sample data, such as the data given in Exercise 1, which confidence interval is wider: the 95% confidence interval or the 80% confidence interval? Why is it wider?

Finding Critical Values. In Exercises 5-8, find the critical value za/2 that corresponds to the given confidence level. 5. 90% 6. 99%

Express the confidence interval 0.255 0.046 in the form of pE

Yellow M&Ms Express the confidence interval (0.0847, 0.153) in the form of P - E < p < p + E. 12. Blue M&Ms Express the confidence interval 0.255 (+-) 0.046 in the form of P - E < p < p + E.

Find the critical value Za/2 that corresponds to the given confidence level. 88%

Express the confidence interval (0.045,0.123) in the form of p^ - E < p < p^+ E.

A drug is used to help prevent blood clots in certain patients. In clinical trials, among 4705 patients treated with the drug, 170 developed the adverse reaction of nausea. Construct a 95% confidence interval for the proportion of adverse reactions. a) Find the best point estimate of the population proportion p.

A drug is used to help prevent blood clots in certain patients. In clinical trials, among 4705 patients treated with the drug, 170 developed the adverse reaction of nausea. Construct a 95% confidence interval for the proportion of adverse reactions. a) identify the value of the margin of error E.

A genetic experiment with peas resulted in one sample of offspring that consisted of 440 green peas and 166 yellow peas. Construct a 90% confidence interval to estimate of the percentage of yellow peas. Based on the confidence interval, do the results of the experiment appear to contradict the expectation that 25% of the offspring peas would be

The initial speed with which a ball is thrown is doubled, with the angle of projection fixed. Is the maximum height to which the ball rises doubled Now, lets say you are also allowed to change the angle as well. Where and when in history might you think this idea was applied How do we apply it now in modern times

The brand manager for a brand of toothpaste must plan a campaign designed to increase brand recognition. He wants to first determine the percentage of adults who have heard of the brand. How many adults must he survey in order to be 80% confident that his estimate is within eight percentage points of the true population percentage? Complete parts

An epidemiologist plans to conduct a survey to estimate the percentage of women who give birth. How many women must be surveyed in order to be 90% confident that the estimated percentage is in error by no more than two percentage points? Complete parts (a) through (c) below. a. Assume that nothing is known about the percentage to be estimated. n =

An epidemiologist plans to conduct a survey to estimate the percentage of women who give birth. How many women must be surveyed in order to be 90% confident that the estimated percentage is in error by no more than two percentage points? Complete parts (a) through (c) below. a. Assume that nothing is known about the percentage to be estimated. n =

An epidemiologist plans to conduct a survey to estimate the percentage of women who give birth. How many women must be surveyed in order to be 95% confident that the estimated percentage is in error by no more than two percentage points? Complete parts (a) through (c) below. a. Assume that nothing is known about the percentage to be estimated. n =

An epidemiologist plans to conduct a survey to estimate the percentage of women who give birth. How many women must be surveyed in order to be 95% confident that the estimated percentage is in error by no more than four percentage points? Complete parts (a) through (c) below. a. Assume that nothing is known about the percentage to be estimated. n

Select all the open loop zeros 02 01 0.5 2.5 03 0.25 4 0.05 10,The BellBoeing V22 Osprey tiltrotor is both an airplane and a helicopter. Its advantage is the ability to rotate its engines and rotors to vertical position for takeoff, landings, and helicopter flight. Then, rotate to a horizonal position to cruise like an airplane. The altitude

An epidemiologist plans to conduct a survey to estimate the percentage of women who give birth. How many women must be surveyed in order to be 95% confident that the estimated percentage is in error by no more than four percentage points? Complete parts (a) through (c) below. a. Assume that nothing is known about the percentage to be estimated. n

An epidemiologist plans to conduct a survey to estimate the percentage of women who give birth. How many women must be surveyed in order to be 99% confident that the estimated percentage is in error by no more than three percentage points? Complete parts (a) through (c) below. a. Assume that nothing is known about the percentage to be estimated. n

Find the critical value t a/2 corresponding to a 95% confidence level. (13.046, 22.15) X= 17.598 Sx= 16.01712719 n=50

Give a brief general description of the number of degrees of freedom. A. The number of degrees of freedom for a collection of sample data is the number of unique, non-repeated sample values. The number of degrees of freedom for a collection of sample data is the number of sample values that are determined after certain restrictions have been

Here are summary statistics for randomly selected weights of newborn girls: n = 36, x = 3180.6 g, s = 700.5 g. Use a confidence level of 99% to complete parts (a) through (d) below. a. Identify the critical value ta/2 used for finding the margin of error. ta/2 =

Here are summary statistics for randomly selected weights of newborn girls: n = 36, x = 3180.6 g, s = 700.5 g. Use a confidence level of 99% to complete parts (a) through (d) below. a. Identify the critical value ta/2 used for finding the margin of error. ta/2 = 2.72 (Round to two decimal places as needed.) b. Find the margin of error. E =

Here are summary statistics for randomly selected weights of newborn girls n 36, x3180.6 g, s 700.5 g. Use a confidence level of 99 to complete parts (a) through (d) below. a. Identify the critical value ta2 used for finding the margin of error. ta2 (Round to two decimal places as needed.) b. Find the margin of error. E 9 (Round to one decimal

Write a brief statement that interprets the confidence interval. Choose the correct answer below. A. There is a 99% chance that the true value of the population mean weight of newborn girls will fall between the lower bound and the upper bound. B. Approximately 99% of sample mean weights of newborn girls will fall between the lower bound and the

A number between 10 and 100 inclusive is selected at random. What is the probability that the number is a multiple of 5, given that none of its digit is a 5?

You Researchers have developed statistical models based on financial ratios that predict whether a company will go bankrupt over the next 12 months. In a test of one such model, the model correctly predicted the bankruptcy of 85% of firms that did in fact fail, and it correctly predicted nonbankruptcy for 74% of firms that did not fail. Suppose

A researcher conducted a study of commitment to a romantic relationship and how much attention a person pays to attractive alternatives. In this study, participants were shown a set of slides of attractive individuals. At the start of the results section, the researcher notes, "The self-reports on the Attentiveness to Alternative Index and the

The probability of obtaining a total of 102 televisions sets or more from a random sample of 40 is?

Use descriptive statistics to summarize the data from Triple Ts study. Based on descriptive statistics, what are your preliminary conclusions about whether the time spent by visitors to the Triple T website differs by background color or font? What are yourpreliminary conclusions about whether time spent by visitors to the Triple T website differs

Ten of the 40 executives responded yes. Based on these sample responses, what is the probability that an oil industry executive will respond yes?

You can put this solution on YOUR website! There are four McBurger restaurants in the Columbus, Georgia, area. The numbers of burgers sold at the respective restaurants for each of the last six weeks are shown below. At the .05 significance level, is there a difference in the mean number sold among the four restaurants, when the factor of week is

You can put this solution on YOUR website! There are four McBurger restaurants in the Columbus, Georgia, area. The numbers of burgers sold at the respective restaurants for each of the last six weeks are shown below. At the .05 significance level, is there a difference in the mean number sold among the four restaurants, when the factor of week is

Suppose out of the population of mean 70 and variance 100 we extracted random samples of size 45 each with mean denoted by X

and variance 100 25. Suppose out of the Population of mean to we extracted Andom samples of size 45 each with mean denoted by (10 marks) A. Determine the mean and standard deviation for x. 3. What is the probability that I will be less than 6r C. What is the Probability that X will be greater than T2 but less than TS SOLUTION

1 A Concluding Example FIGURE 5.9 Residuals from the food expenditure regression. Chapter 5 TwoVariable Regression Inter Let us return to Example 3.2 about food expenditure in India. Using the data given in Equa tion (3.7.2) and adopting the format of Equation (5.11.1), we obtain the following expen diture equation Food Exp, 94.2087 0.4368 Total

Difference unitary measurnment

3% of cars are defective if 1,698 were defective how many vehicles in total was produced

In high school, the probability of a student being a girl is 0.35. If 50 students are randomly selected, find, A. The probability that more than 27 will be girls. B. The probability that more than 20 will not be girls, and C. The probability that more than 5 but less than 30 students will be girls

Solve this question The American Hospital Association publishes information about U.S. hospital and nursing homes in Hospital Statistics. The following contingency table provides a cross classification of U.S. hospitals and nursing homes by type of facility and numbers of beds. Facility Number of beds 24 or fewer 25-74 75 or more General 260 1586

Kencoff Company Ltd. is a coffee manufacturing company that was incorporated on 1 January 2020. The company commenced its operations on 2 May 2020 after incurring the following expenditure. Sh. Factory land and building 82.000.000 Conveyor belts 6,200,000 Furniture and fittings 350,000 Farin labour quarters 4.800.000 Coffee milling machinery

Examine the data collected by the World Bank on the number of companies that are incorporated and are listed on a countrys stock exchange at the end of the year. Click to download the data in your preferred format. Find the correlation for the years 2007 and 2017. Round to three decimal places. correlation:

Examine the data collected by the World Bank on the number of companies that are incorporated and are listed on a countrys stock exchange at the end of the year. Click to download the data in your preferred format. Find the correlation for the years 2007 and 2017. Round to three decimal places. correlation:

Using the harmonic mean, find each of these. a. A salesperson drives 300 miles round trip at 30 miles per hour going to Chicago and 45 miles per hour returning home. Find the average miles per hour. b. A bus driver drives the 50 miles to West Chester at 40 miles per hour and returns driving 25 miles per hour. Find the average miles per hour.

A study of 40 U.S. cardiac care centers showed the following ratios of nurses to beds. (a) Pre pare a dot plot. (b) Prepare a frequency distribution and histogram (you may either specify the bins yourself or use automatic bins). (c) Describe the distribution, based on these displays. Nurses. 1.48 1.16 1.24 1.52 1.30 1.28 1.68 1.40 1.12 0.98 0.93

Alexandra Damonte will be building a new resort in Myrtle Beach, South Carolina. She must decide how to design the resort based on the type of activities that the resort will offer to its customers. A recent poll of 300 potential customers showed the following results about customers preferences for planned resort activities: Like planned

Given this data set (12, 9, 15, 13, and 11) with a mean of 12.00, find the following: a. N b. (x-m) c. (x-m) 2

The Economic Policy Institute periodically issues reports on wages of entry level workers. The institute reported that entry level wages for male college graduates were $21.68 per hour and for female college graduates were $18.80 per hour in 2011 (Economic Policy Institute website, March 30, 2012). Assume the standard deviation for male graduates

Suppose a survey asks, "Do you own any CDs?" Explain how this could be interpreted in more than one way. Suggest a way in which the question could be improved

Q1: Find the z value to the right of the mean so that (2 points each) 1. 54.78% of the area under the distribution curve lies to the left of it. 2. 69.85% of the area under the distribution curve lies to the left of it. 3. 88.10% of the area under the distribution curve lies to the left of it. Q2: An instructor gives a 100-point examination in

Z-Score For this assignment, use the data you created in your W1 Midweek Assignment. Using Microsoft Excel and following the instructions given in your lecture, convert each subject's age and height into a z-score. Using the z-score of 1.645 for the 5 percent cutoff and the z-score of 1.96 for the 2.5 percent in the tail, identify the subject

An insurance salesman visits up to three clients each day, hoping to sell a new policy. He stops for the day once he makes a sale. Each client independently decides whether to buy a policy. 10 10% of clients purchase the policy. Let X be defined as the number of sales he made in a day. Find the value of ( = 0 ) P(X=0). (Write your answer upto

Use the given information to find the number of degrees of freedom, the critical values x and x, and the confidence interval estimate of o. It is reasonable to assume that a simple random sample has been selected from a population with a normal distribution. Nicotine in menthol cigarettes 90% confidence; n = 21, s = 0.25 mg . df = 20 x2L =

A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with the drug, 11 subjects had a mean wake time of 95.1 min and a standard deviation of 43.8 min. Assume that the 11 sample values appear to be from a normally distributed population and construct a 95% confidence

A clinical trial was conducted to test the effectiveness of a drug used for treating insomnia in older subjects. After treatment with the drug, 12 subjects had a mean wake time of 97.5 min and a standard deviation of 41.8 min. Assume that the 12 sample values appear to be from a normally distributed population and construct a 95% confidence

Construct a 90% confidence interval for the population standard deviation o at Bank A. Bank A 6.4 6.6 6.7 6.8 7.1 7.2 7.6 7.8 7.8 7.8

Construct a 90% confidence interval for the population standard deviation o at Bank B. Bank B 4.2 5.4 5.9 6.1 6.6 7.7 7.7 8.6 9.3 10.0

Construct a 90% confidence interval for the population standard deviation o at Bank A. Bank A 4.2 5.4 5.9 6.1 6.6 7.7 7.7 8.6 9.3 10.0

The pulse rates of 152 randomly selected adult males vary from a low of 37 bpm to a high of 117 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 95% confidence that the sample mean is within 3 bpm of the population mean. Complete parts (a) through (c) below. a. Find the sample size

The pulse rates of 152 randomly selected adult males vary from a low of 37 bpm to a high of 117 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 95% confidence that the sample mean is within 3 bpm of the population mean. Complete parts (a) through (c) below. a. Find the sample size

The pulse rates of 152 randomly selected adult males vary from a low of 37 bpm to a high of 117 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 95% confidence that the sample mean is within 3 bpm of the population mean. Complete parts (a) through (c) below. a. Find the sample size

The pulse rates of 152 randomly selected adult males vary from a low of 37 bpm to a high of 117 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 95% confidence that the sample mean is within 3 bpm of the population mean. Complete parts (a) through (c) below. a. Find the sample size

Assume that females have pulse rates that are normally distributed with a mean of p = 72.0 beats per minute and a standard deviation of o = 12.5 beats per minute. Complete parts (a) through (c) below. a. If 1 adult female is randomly selected, find the probability that her pulse rate is less than 75 beats per minute. The probability is

Assume that females have pulse rates that are normally distributed with a mean of p = 72.0 beats per minute and a standard deviation of o = 12.5 beats per minute. Complete parts (a) through (c) below. b. If 16 adult females are randomly selected, find the probability that they have pulse rates with a mean less than 75 beats per minute. The

Based on a survey, assume that 42% of consumers are comfortable having drones deliver their purchases. Suppose that we want to find the probability that when six consumers are randomly selected, exactly three of them are comfortable with delivery by drones. Identify the values of n, x, p, and q. The value of n is ____ the value of x is ____ the

Assume that different groups of couples use a particular method of gender selection and each couple gives birth to one baby. This method is designed to increase the likelihood that each baby will be a girl, but assume that the method has no effect, so the probability of a girl is 0.5. Assume that the groups consist of 35 couples. Complete parts

You are certain to get a number or a face card when selecting cards from a shuffled deck. Express the indicated degree of likelihood as a probability value between 0 and 1 inclusive. The probability Is

Among 450 randomly selected drivers in the 16 - 18 age bracket, 374 were in a car crash in the last year. If a driver in that age bracket is randomly selected, what is the approximate probability that he or she will be in a car crash during the next year? Is it unlikely for a driver in that age bracket to be involved in a car crash during a year?

The sample space listing the eight simple events that are possible when a couple has three children is {bbb, bbg, bgb, ogg, gbb, gbg, ggb, ggg}. After identifying the sample space for a couple having four children, find the probability of getting four girls and no boys. Identify the sample space for a couple having four children. (Use a comma to

What is judgement sampling?Explain with a suitable example.

What is convenience sampling?Explain with a suitable example.