Questions and Answers of Statistics Informed Decisions

Suppose there are n independent trials of an experiment with k > 3 mutually exclusive outcomes, where pi represents the probability of observing the ith outcome. The _____________for
A ______________ test is an inferential procedure used to determine whether a frequency distribution follows a specific distribution.
You want to invest in a stock and have narrowed your choices down to either Citibank (C) or Wells Fargo (WFC). To help you decide which stock to invest in, you decide to compare weekly rates of
A nurse was interested in discovering whether men have more variability in their systolic blood pressure than women. She randomly selects 20 males and 17 females from the surgical floor of her
Refer to Problem 5. Determine the probability of making a Type II error if the true population proportion is 0.63. Assume the test is conducted at the a = 0.05 level of significance. What is the
Standard deviation rate of return is a measure of risk in the stock market. An investment manager claims that the standard deviation rate of return for his portfolio is less than the general market,
A test is conducted at the a = 0.05 level of significance. What is the probability of a Type I error?
How do the probability of making a Type II error and effect size play a role in determining an appropriate sample size when performing a hypothesis test?
What effect does increasing the sample size have on the power of the test, assuming all else remains unchanged?
To test H0: p = 0.40 versus H1: p 7 0.40, a simple random sample of n = 200 individuals is obtained and x = 84 successes are observed.(a) What does it mean to make a Type II error for this test?(b)
Explain what it means to make a Type II error.
A simple random sample of size n = 16 is drawn from a population that is normally distributed. The sample variance is found to be 13.7. Test whether the population variance is greater than 10 at the
(a) Determine the critical value for a right-tailed test of a population standard deviation with 16 degrees of freedom at the a = 0.01 level of significance.(b) Determine the critical value for
The headline reporting the results of a poll conducted by the Gallup organization stated “Majority of Americans at Personal Best in the Morning.” The results indicated that a survey of 1100
Explain what “statistical significance” means.
The following is a quotation from Sir Ronald A. Fisher, a famous statistician.For the logical fallacy of believing that a hypothesis has been proved true, merely because it is not contradicted by the
The _________________ is the probability of making a Type I error.
The given data represent the wait time (in seconds) for a random sample of 14 individuals before connecting with a customer service agent.(a) A boxplot of the data is shown next. The quality control
A tennis enthusiast wants to estimate the mean length of men’s singles matches held during the Wimbledon tennis tournament. From the Wimbledon history archives, he randomly selects 40 matches
Find the critical values x21-a>2 and x2a>2 required to construct a confidence interval about σ for the given level of confidence and sample size.(a) 98% confidence; n = 16(b) 90% confidence; n
To estimate proportions using bootstrapping methods, report successes as 1 and failures as 0. Then follow the sample procedures that we used to estimate a mean using bootstrapping. Suppose a random
The following data represent the annual 2011 salary (in thousands of dollars) of a random sample of professional baseball players.(a) Draw a boxplot of the data. Explain why a t-interval cannot be
The following data represent the prices for a 4 GB flash memory card from online retailers. Treat these data as a simple random sample of all online retailers. In Problem 35 from Section 9.2, we
The 112th Congress of the United States of America has 535 members, of which 87 are women. An alien lands near the U.S. Capitol and treats members of Congress as a random sample of the human race. He
A Bernoulli random variable is a variable that is either 0 (a failure) or 1 (a success). The probability of success is denoted p.(a) What proportion of the intervals do you expect to include the
In Problem, determine the critical value za/2 that corresponds to the given level of confidence. 90%
The value za/2 represents the ___________________of the distribution.
A ______________is the value of a statistic that estimates the value of a parameter.
In a town of 500 households, 220 have a dog. The population proportion of dog owners in this town (expressed as a decimal) is p = ______________.
In Problem, a normal probability plot of a simple random sample of data from a population whose distribution is unknown was obtained. Given the normal probability plot, is there reason to believe the
Find the value of z0.04.
You suspect a pair of dice to be loaded and conduct a probability experiment by rolling each die 400 times. The outcome of the experiment is listed in the table below. Do you think the dice are
In January 2011, the mean amount of money lost per visitor to a local riverboat casino was $135. Do you think the median was more than, less than, or equal to this amount? Why?
The data below represent the ages of the presidents of the United States (from George Washington through Barack Obama) on their first days in office.President Cleveland’s age is listed twice, 47
The following time-series plot shows the annual unemployment and inflation rates for the years 1988 through 2009.(a) Estimate the unemployment and inflation rates for 1992.(b) Estimate the
The following time-series graph shows the annual U.S. motor vehicle production from 1990 through 2008.(a) Estimate the number of motor vehicles produced in the United States in 1991.(b) Estimate the
The following relative frequency ogive represents the SAT math scores of college-bound students.(a) What is the class width? How many classes are represented in the graph?(b) What are the lower and
The relative frequency ogive on the following page represents the ACT composite score for the high school graduating class of 2010.(a) Estimate the percentage of students who had a composite score of
Deaths by legal intervention refers to injuries inflicted by law-enforcement agents in the course of arresting or attempting to arrest lawbreakers, suppressing disturbances, maintaining order, and
Age of Population The following frequency polygon shows the age distribution of U.S. residents below 100 years of age on July 1, 2009.(a) What is the class width? How many classes are represented in
What are time-series data?
What is an ogive?
A poll is conducted in which 500 people are asked whom they plan to vote for in the upcoming election.
Researchers wanted to know if there is a link between proximity to high-tension wires and the rate of leukemia in children. To conduct the study, researchers compared the rate of leukemia for
Discuss the differences between discrete and continuous variables.
Only 12 men have walked on the moon. The average age of these men at the time of their moonwalks was 39 years, 11 months, 15 days.
Use In a national survey on substance abuse, 10.0% of respondents aged 12 to 17 reported using illicit drugs within the past month.
Following the 2010 national midterm election, 18% of the governors of the 50 United States were female. - parameter
In Problem, a normal probability plot of a simple random sample of data from a population whose distribution is unknown was obtained. Given the normal probability plot, is there reason to believe the
Find the value of z0.20.
If X is normal random variable with mean 40 and standard deviation 10 and P(X < 38) = 0.4207, then P (X ≤ 38) = _______________.
If X is a normal random variable with mean 40 and standard deviation 10 and P(X > 45) = 0.3085, then P(X < 35) = __________.
The notation za is the z-score that the area under the standard normal curve to the right of za is ___________.
The number of cars that arrive at a bank’s drive-through window between 3:00 p.m. and 6:00 p.m. on Friday follows a Poisson process at the rate of 0.41 car every minute. Compute the probability
Data from the National Center for Health Statistics show that spina bifida occurs at the rate of 28 per 100,000 live births. Let the random variable X represent the number of occurrences of spina
According to the National Center for Health Statistics, the common cold occurs at the rate of 23.6 colds per 100 people during the course of a year in the 18- to 24-year-old age group. Let the random
From 1900 to 2010 (111 years), Florida suffered 29 direct hits from major (category 3 to 5) hurricanes. Assume that this was typical and the number of hits per year follows a Poisson
In Problem, the random variable X follows a Poisson process with the given mean.Assuming μ = 7, compute(a) P(10) (b) P(X < 10)(c) P(X ≥ 10) (d) P(7 ≤ X ≤ 9)
The potholes on a major highway in the city of Madison occur at the rate of 3.4 per mile. The random variable X is the number of potholes in 10 miles of randomly selected highway.
The flaws in a piece of timber occur at the rate of 0.07 per linear foot. The random variable X is the number of flaws in the next 20 linear feet of timber.
The phone calls to a computer software help desk occur at the rate of 5 per minute between 3:00 p.m. and 4:00 p.m. The random variable X is the number of phone calls between 3:10 p.m. and 3:20 p.m.
The hits to a Web site occur at the rate of 10 per minute between 7:00 p.m. and 9:00 p.m. The random variable X is the number of hits between 7:30 p.m. and 7:35 p.m.
State the conditions required for a random variable X to follow a Poisson process.
If the 2011 Hyundai Genesis has 2 engine types, 2 vehicle styles, 3 option packages, 8 exterior color choices, and 2 interior color choices, how many different Genesis’s are possible?
List all combinations of five objects a, b, c, d, and e taken three at a time without replacement.
Compute the probability of the event F = “a number divisible by three.”For Problems, let the sample space be S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}. Suppose that the outcomes are equally likely.
Compute the probability of the event E = {1, 3, 5, 10}.For Problem, let the sample space be S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}. Suppose that the outcomes are equally likely.
How many distinguishable DNA sequences can be formed using one A, four Cs, three Gs, and four Ts?
How many distinguishable DNA sequences can be formed using three As, two Cs, two Gs, and three Ts?
If two events E and F are independent, P(E and F ) = _____ .
The golf ball is not a Top-Flite.In Problems, a golf ball is selected at random from a golf bag. If the golf bag contains 9 Titleists, 8 Maxflis, and 3 Top-Flites, find the probability of each event.
The golf ball is not a Titleist.In Problems, a golf ball is selected at random from a golf bag. If the golf bag contains 9 Titleists, 8 Maxflis, and 3 Top-Flites, find the probability of each event.
The golf ball is a Maxfli or Top-Flite.In Problem, a golf ball is selected at random from a golf bag. If the golf bag contains 9 Titleists, 8 Maxflis, and 3 Top-Flites, find the probability of each
The golf ball is a Titleist or Maxfli.In Problems, a golf ball is selected at random from a golf bag. If the golf bag contains 9 Titleists, 8 Maxflis, and 3 Top-Flites, find the probability of each
In Problem, find the probability of the indicated event if P(E) = 0.25 and P(F) = 0.45.If P(F) = 0.30, P(E or F) = 0.65, and P(E and F) = 0.15, find P(E).
In Problem, find the probability of the indicated event if P(E) = 0.25 and P(F) = 0.45.If P(E) = 0.60, P(E or F) = 0.85, and P(E and F) = 0.05, find P(F).
In Problems, find the probability of the indicated event if P(E) = 0.25 and P(F) = 0.45.Find P(Ec).
List the outcomes in F and H. Are F and H mutually exclusive?In Problem, a probability experiment is conducted in which the sample space of the experiment is S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
List the outcomes in E and G. Are E and G mutually exclusive?In Problem, a probability experiment is conducted in which the sample space of the experiment is S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
List the outcomes in E or H. Now find P(E or H) by counting the number of outcomes in E or H. Determine P(E or H) using the General Addition Rule.In Problem, a probability experiment is conducted in
List the outcomes in F or G. Now find P(F or G) by counting the number of outcomes in F or G. Determine P(F or G) using the General Addition Rule.In Problem, a probability experiment is conducted in
List the outcomes in F and G. Are F and G mutually exclusive?In Problem, a probability experiment is conducted in which the sample space of the experiment is S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
List the outcomes in E and F. Are E and F mutually exclusive?In Problem, a probability experiment is conducted in which the sample space of the experiment is S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
Which of the assignments of probabilities should be used if tails is twice as likely to occur as heads? Sample Space НН Assignments HT TH TT A 4 4 4 B 5 16 16 D E 4 F 9. |3|의1-21_8 4-9 |40|3|의1
Which of the assignments of probabilities should be used if the coin is known to always come up tails? Sample Space НН Assignments HT TH TT A 4 4 4 B 5 16 16 D E 4 F 9. |3|의1-21_8 4-9 |40|3|의1
Which of the assignments of probabilities should be used if the coin is known to be fair?
A cricket chirps 14.5 times per second when it is 92°F outside. Is this observation influential? Why?
The scatter diagram represents the percentage of the population with a bachelor’s degree, x, and teen birthrates (births per 1000 15- to 19-year-olds), y, for the 50 states and Washington, DC, in
In the 2009 Current Population Survey conducted by the U.S. Census Bureau, two average household incomes were reported: $49,777 and $67,976. One of these averages is the mean and the other is the
The following is a USA Today type graph. Do you think the graph is misleading? Why? If you think it is misleading, what might be done to improve the graph? Most Popular Ways to Save for College
The following frequency distribution represents the closing prices (in dollars) of homes sold in a Midwest city.(a) Construct a cumulative frequency distribution.(b) Construct a cumulative relative
The cumulative relative frequency for the last class must always be 1. Why?
The following data represent the earned-run average (ERA) of the top 40 pitchers in both the American League and National League in 2010.ERA is the average number of earned runs given up per 9
The following time-series plot shows the prize money (in pounds) awarded at the Wimbledon Tennis Championship to the winners of the men’s singles and ladies’ singles competitions from 1995
A survey of adult men and women asked, “Which one of the following jobs would you most like to have?” The results of the survey are shown in the table.(a) Construct a relative frequency
In a relative frequency distribution, what should the relative frequencies add up to?
Describe what is meant by an experiment that has a completely randomized design. Contrast this experimental design with a randomized block design.
In the 2011 NCAA Football Championship Game, quarterback Cam Newton completed 59% of his passes for a total of 265 yards and 2 touchdowns.In determine whether the underlined value is a parameter or a
In a survey of 1011 people age 50 or older, 73% agreed with the statement “I believe in life after death.”In determine whether the underlined value is a parameter or a statistic.
Research the placebo effect and the Hawthorne effect. Write a paragraph that describes how each affects the outcome of an experiment.

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