Questions and Answers of Essentials Of Statistics

Given a z score of 1.5, a mean of 40, and a standard deviation of 5, what is the corresponding raw score? What is the corresponding t score?
Questions 6a through 6d are based on a distribution of scores with X = 75 and standard deviation = 6.38. Draw a small picture to help you see what's required.a. What is the probability of a score
Using the NORM.S.DIST function, compute the probability that a score would fall between+ 1 and +2 z scores. Remember, you don't need any raw score values because a z score of 1 is a z score of 1 is a
Jake needs to score in the top 10% on a fitness test in order to earn a physical fitness certificate. The class mean is 78, and the standard deviation is 5.5. What raw score does he need to get that
What is the value of understanding the central Limit theorem?
Why doesn't it make sense to simply combine, for example, test grades across different courses- just take an average and call it a day?
Who is the better student, relative to his or her classmates? Here's all the information you ever wanted to know. Math Class Mean Class Standard Deviation 81 2 Reading Class Mean 87 Class Standard 10
And, last but not least, our favorite fun questions: Why is there always a chance for rain (even if the sky is sunny and the forecast is clear)? And why is the only time there is a 100% chance of
Why is significance an important construct in the study and use of inferential statistics?
What's wrong with the following statements?a. A Type I error of .05 means that in 5 out of 100 tests of the research hypothesis, I will reject a true null hypothesis.b. lt is possible to set the Type
What does chance have to do with the testing of the research hypothesis for significance?
Given the following information, would your decision be to reject or fail to reject the null hypothesis? (Set the level of significance at .05 for decision making.) Provide an explanation for your
Why is it "harder" to find a significant outcome (all other things being equal) when the research hypothesis is being tested at the .01 rather than the .05 level of significance?
Why should we think in terms of "failing to reject" the null rather than just accepting it?
What does the actual critical value represent?
What does the obtained value represent?
In Figure 9.2, there is a striped area in the right-hand part of the curve.a. What does that area represent?b. If you tested the research hypothesis at a more rigorous level (say at .01 rather than
When is it appropriate to use the one-sample Z-test?
What's with the Z in Z-test? In what way is it similar to a simple z or standard score?
For the following situations, write out a research hypothesis:a. Bob wants to know if the weight loss for his group on the chocolate-only diet is representative of weight loss in a large population
Flu cases this past flu season (4 months or 20 weeks) in the Butterfield, Kansas, school system were about 1 5 per week. For the entire state, the weekly average was 16 and the standard deviation
Mark's class just took the admission test for business school and averaged 83.4. contains the population of scores for the 10 other classes in Mark's university. How did Mark's class do?
Sales at Joe's BBQ in Salina, Kansas, were $$35,676$ for the first week of June 2015. How did Joe do compared with the rest of the barbecue restaurants in the county association?
Interview someone who uses statistics in his or her everyday work. It might be your adviser, an instructor, a researcher who lives on your block, a market analyst for a company, a city planner, or
We hope that you are part of a study group or, if that is not possible, that you have a telephone, e-mail, instant messaging, or webcam study buddy (or even more than one). And, of course, plenty of
Search through your local newspaper (or any other publication) and find the results of a survey or interview about any topic.Summarize the results and do the best job you can describing how the
Go to the library (either in person or online) and find a copy of a journal article in your own discipline. Then, go through the article and highlight the section (usually the "Results" section)where
Find five websites that contain data on any topic and write a brief description of what type of information is offered and how it is organized. For example, if you go to the mother of all data sites,
And the big extra-credit assignment is to find someone who actually uses Excel for daily data analysis needs. Ask why he or she uses Excel rather than a more specialized program such as SPSS or
Finally, as your last in this first set of exercises, come up with five of the most interesting questions you can about your own area of study or interest. Do your best to come up with questions for
The efficiency of the rank correlation test is 0.91. What does that value tell us about the test?
True or false: If there is no linear correlation between systolic and diastolic blood pressure, then those two variables are not related in any way.
True or false: If the sample data lead us to the conclusion that there is sufficient evidence to support the claim of a linear correlation between systolic and diastolic blood pressure, then we could
If each systolic reading is exactly twice the diastolic reading, what is the value of the linear correlation coefficient r?
If you had computed the value of the linear correlation coefficient to be 3.335, what should you conclude?
If the sample data were to result in the scatterplot shown here, what is the value of the linear correlation coefficient r?
The table below lists days of the week selected by a random sample of 1005 subjects who were asked to identify the day of the week that is best for quality family time (based on results from a
Without performing actual calculations, examine the frequencies in the table given with Exercise 1. Do you expect the value of the X2 test statistic to be large or small? Do you expect the P-value to
Goodness-of-Fit Test For the goodness-of-fit test described in Exercise 1, identify the number of degrees of freedom and the critical value of X2, assuming a 0.05 significance level.Exercise 1The
Is the hypothesis test left-tailed, right-tailed, or two-tailed?The table lists frequencies for randomly selected nonfatal occupation injuries arranged according to day of the week. Assume that we
Given that the P-value for the hypothesis test is 0.971, what do you conclude?The table lists frequencies for randomly selected nonfatal occupation injuries arranged according to day of the week.
Is the hypothesis test left-tailed, right-tailed, or two-tailed?Randomly selected subjects were asked about the use of marijuana for medical purposes. Assume that we want to use a 0.05 significance
Find the number of degrees of freedom and the critical value.Randomly selected subjects were asked about the use of marijuana for medical purposes. Assume that we want to use a 0.05 significance
Given that the P-value for the hypothesis test is 0.836, what do you conclude?Randomly selected subjects were asked about the use of marijuana for medical purposes. Assume that we want to use a 0.05
The following histogram is obtained from the daily rainfall amounts (in.) in Boston for a year. If we want to conduct a hypothesis test of a claim about the mean, there is a requirement that the
For the methods of this section, which of the following statements are true?a. The requirement of a simple random sample is satisfied if we have matched pairs of voluntary response data.b. If we have
Identify the null and alternative hypotheses resulting from the claim that the proportion of women who agree with the given statement is equal to the proportion of men who agree.Randomly selected
When testing the claim that p1 = p2, a test statistic of z = 2.04 is obtained. Find the P-value obtained from this test statistic.Randomly selected subjects were asked if they agreed with the
Listed below are the costs (in dollars) of repairing the front ends and rear ends of different cars when they were damaged in controlled low-speed crash tests (based on data from the Insurance
Determine whether the following statement is true or false: When testing a claim about the means of two independent populations, the alternative hypothesis can never contain the condition of equality.
Determine whether the following statement is true or false: When testing the claim that the mean annual income of statistics professors in New York is equal to the mean annual income of statistics
Determine whether the following statement is true or false: When using the methods of this chapter to test a claim that two population proportions are equal, each of the two samples must satisfy the
The USA Today Web site posted this question: “Have you considered getting a home generator for backup power?” Among 928 Internet users who chose to respond, 41% answered “yes.” If we use
Students of the author collected a simple random sample of times (sec) of wristwatch errors, and a few of those times are listed below. Negative values correspond to watches that are running ahead of
Refer to the hypothesis test described in Exercise 1.a. Is the hypothesis test left-tailed, right-tailed, or two-tailed?b. If the requirements are satisfied, what distribution should be used for the
If we use technology to conduct the hypothesis test described in Exercise 1, we get a P-value of 0.1150.a. What should we conclude about the null hypothesis?b. What is the final conclusion that
In a recent Gallup poll of 511 adults, 64% said that they were in favor of the death penalty for a person convicted of murder. We want to use a 0.01 significance level to test the claim that the
Find the P-value in a test of the claim that the mean IQ score of acupuncturists is equal to 100, given that the test statistic is z = -2.00.
The claim is that for the nicotine amounts in king-size cigarettes, μ > 1.10 mg. The sample size is n = 25 and the test statistic is t = 3.349. Either use technology to find the P-value or use
The claim is that for the tar amounts in king-size cigarettes, μ > 20.0 mg. The sample size is n = 25 and the test statistic is t = 1.733.Either use technology to find the P-value or use Table
The claim is that for measurements of standard head injury criteria in car crash tests, μ = 475 HIC (standard head injury condition units). The sample size is n = 21 and the test statistic is t =
Six human skulls from around 4000 b.c. were measured, and the lengths have a mean of 94.2 mm and a standard deviation of 4.9 mm. If you want to construct a 95% confidence interval estimate of the
Refer to Exercise 7 and assume that the requirements are satisfied. Find the critical values that would be used to construct a 95% confidence interval estimate of σ.Exercise 7Six human skulls from
The test statistic of z = 2.00 is obtained when testing the claim that p > 0.5.Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values.
The test statistic of z = -2.00 is obtained when testing the claim that p Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value =
With H1: p ≠ 2/3, the test statistic is z = 2.50.Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value = area to the left of the
With H1: p Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value = area to the left of the test statistic Left-tailed Left Start
With H1: p > 7/8, the test statistic is z = 2.88.Assume that the significance level is α = 0.05; use the given statement and find the P-value and critical values. P-value = area to the left of
We can test a claim about a population proportion using the P-value method of hypothesis testing or the critical value method of hypothesis testing, or we could base our conclusion on a confidence
Confidence level is 95%, σ is known to be $4,385,000, and the dotplot of a sample of Red Sox baseball player salaries is as shown below.Assume that we want to construct a confidence interval. Do one
Confidence level is 90%, σ is not known, and the dotplot of IQ scores of 20 randomly selected statistics instructors is as shown below.Assume that we want to construct a confidence interval. Do one
Confidence level is 99%, σ is not known, and the dotplot of a sample of 40 values of professional baseball player salaries is as shown below.Assume that we want to construct a confidence interval.
Confidence level is 99%, σ is known to be $4,385,000, and the dotplot of 40 sample values of professional baseball players is as shown in Exercise 7.Assume that we want to construct a confidence
Find the indicated critical value.z0.025
Find the indicated critical value.z0.01
Find the indicated critical value.z0.05
Find the indicated critical value.z0.03
Find the probability of an IQ less than 85.
Mensa International calls itself “the international high IQ society,” and it has more than 100,000 members. Mensa states that “candidates for membership of Mensa must achieve a score at or
Find P80, the 80th percentile for the red blood cell counts of women.
If 25 women are randomly selected, find the probability that the mean of their red blood cell counts is less than 4.444.Assume that red blood cell counts of women are normally distributed with a mean
What percentage of women have red blood cell counts in the normal range from 4.2 to 5.4?Assume that red blood cell counts of women are normally distributed with a mean of 4.577 and a standard
An Office Team survey of 150 executives found that 93.3% of them said that they would be concerned about gaps in a résumé of a job applicant. Based on these results, such randomly selected groups
A new integrated circuit board is being developed for use in computers. In the early stages of development, a lack of quality control results in a 0.2 probability that a manufactured integrated
If boys and girls are equally likely, groups of 400 births have a mean of 200 girls and a standard deviation of 10 girls. Is 232 girls in 400 births an unusually high number of girls?
If boys and girls are equally likely, groups of 400 births have a mean of 200 girls and a standard deviation of 10 girls. Is 185 girls in 400 births an unusually low number of girls?
If six people are randomly selected, find the probability that none of them has brown eyes.Assume that 40% of the population has brown eyes based on data from Dr. P. Sorita at Indiana University.
Find the probability that among six randomly selected people, exactly four of them have brown eyes.Assume that 40% of the population has brown eyes based on data from Dr. P. Sorita at Indiana
In the month preceding the creation of this exercise, the author made no phone calls on 19 of the 30 days in the month. Assume that 10 days from that month are randomly selected with replacement.
A denote the event of placing a $1 straight bet on the Florida Play 4 lottery and winning. The chance of event A occurring is 1 in 10,000. What is the value of P(A)? What is the value of P(A)?
Given that the following statement is incorrect, rewrite it correctly: “The probability of a baby being born a boy is 50–50.”
Which of the following values are not probabilities?5:2 3/7 7/3 -0.9 0.123 123/456 456/123 0 1
“Who was the 14th president of the United States: Taylor, Fillmore, Pierce, or Buchanan?” If you make a random guess for the answer to that question, what is the probability that your answer is
“Which of the following is the mean of the first 100 digits of pi after the decimal point: 4.4, 4.5, 4.6, 4.7, or 4.8?” If you make a random guess for the answer to that question, what is the
When rolling a single die, what is the probability that the outcome is 7?
Exactly 205 girls.Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that
Exactly 380 girls.Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that
Exactly 111 girls.Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that
Assume that 400 births are randomly selected. Use subjective judgment to determine whether the given outcome is unlikely, and also determine whether it is unusual in the sense that the result is far
When arriving at the traffic light closest to the author’s home, there is a 25% chance that the light will be red.Express the indicated degree of likelihood as a probability value between 0 and 1.

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