Question: In hypothesis tests, if the significance level

> A researcher measures the braking reaction time of a subject and records a value of 2.4 seconds, but the subject’s actual braking reaction time is 1.9 seconds. What is the relative error?

> Tempered glass is used for car windows because it is much tougher than regular glass. A researcher tests the strength of samples of glass by heating them at 620°C, which is the industry standard.

> A researcher measures the braking reaction time of a subject and records a value of 2.4 seconds, but the subject’s actual braking reaction time is 1.9 seconds. What is the absolute error?

> You want to conduct a survey of parents of elementary school students in Minneapolis by using telephone calls instead of personal visits. Assume you have directories listing telephone numbers of all (or almost all) parents at each of the city’s elementar

> What is the level of measurement of the values described in Exercise 1 (nominal, ordinal, interval, or ratio)?

> Refer to the table in Exercise 9. If the net profit in the sixth year is projected to be 5% less than the net profit in the fifth year, what is that projected sixth-year net profit?

> Braking reaction times of 36 randomly selected licensed drivers are measured. Are those data considered quantitative or qualitative? If quantitative, are those values continuous or discrete?

> If a statistical study is carefully conducted in every possible way, then: (a) Its results must be correct; (b) We can have confidence in its results, but it is still possible that the results are not correct; (c) We say that the study is perfectly biase

> Consider a survey of randomly selected people in which it is found that participants who used sunscreen were more likely to have been sunburned in the past year. Which explanation for this result seems most likely? (a) Sunscreen is useless; (b) The peop

> Consider a study in which you measure the weights of dolphins. The variable of interest in this study is: (a) The size of the sample; (b) The weights of dolphins; (c) The average (mean) weight of all dolphins.

> From the poll results given in Exercise 11, can we safely conclude that the majority of people are most annoyed by the use of “whatever” in conversation?

> In a Marist Poll, respondents chose the most annoying phrases used in conversation. Among the 864 subjects who were surveyed, 51% chose “whatever.” The survey has a margin of error of 3 percentage points. Identify the range of values for the confidence i

> If all subjects in the aspirin treatment group are athletes and all subjects in the control group are not athletes, then there is a danger of which of the following: (a) Samples those are too small; (b) Confounding; (c) Blinding.

> The Nielsen Company installs devices in homes to record the TV shows that are watched. The results are then used to provide ratings identifying which shows are being viewed more than others.

> Figure 3.36 on the next page depicts the annual high values of the Dow Jones Industrial Average (DJIA) for stocks. How is this graph misleading? How could it be drawn so that it is not misleading? In this case, would the graph change dramatically if it w

> In a Gallup poll of 1018 adults, it was found that 22% smoked cigarettes in the past week.

> If we see a placebo effect, it means: (a) The experiment was not really double-blind; (b) The experimental groups were too small; (c) Pulse rates were lowered among some of those in the placebo group.

> The purpose of the placebo is: (a) To prevent participants from knowing whether they belong to the treatment group or the control group; (b) To distinguish between the cases and the controls in a case-control study; (c) To determine whether pulse rates a

> The subjects do not know whether they are given aspirin or a placebo, and the evaluators who measure the pulse rates also do not know. This trial is: (a) Single-blind; (b) Double-blind; (c) Not blinded.

> Is this an experiment or an observational study?

> Are the survey results a sample or a census?

> If we learn that the sample is representative of the population, which of the following best describes the results: (a) The results found for the sample are similar to those we would find for the entire population; (b) The sample is very large; (c) The

> What do we mean by critical values for significance in a hypothesis test for the population proportion? How does this compare to the critical values for statistical significance for a population mean? How do we use this for making decisions about the hyp

> When testing a claim about a population proportion, what is a standard score, z, for the sample proportion, pˆ?

> What do n, p, pˆ , and P-value represent?

> Figure 3.35 shows the median home prices in regions of the United States. How is the graph misleading? How could it be drawn so that it is not misleading? Figure 3.35

> The Genetics and IVF Institute conducted a clinical trial of the YSORT method designed to increase the probability of conceiving a boy. As of this writing, 291 babies were born to parents using the YSORT method, and 82% of them were boys. Test the claim

> The Department of Transportation used a retrospective study to determine that air bags save lives.

> The Genetics and IVF Institute conducted a clinical trial of the XSORT method designed to increase the probability of conceiving a girl. As of this writing, 945 babies were born to parents using the XSORT method, and 93% of them were girls. Test the clai

> In clinical tests of the drug Lipitor, 863 patients were treated with the drug and 19 of them experienced flu symptoms (based on data from Parke-Davis). Test the claim that the percentage of treated patients with flu symptoms is greater than the 1.9% rat

> According to the Energy Information Administration, 53.0% of U.S. households used natural gas for heating in 1997. A recent survey of 3600 randomly selected U.S. households showed that 54.0% used natural gas. Use a 0.05 significance level to test the cla

> When 3011 adults were surveyed in a Pew Research Center poll, 2198 said that they use the Internet. Is it accurate for a newspaper reporter to write that “3/4 of all adults use the Internet”? Why or why not?

> In a study of 1228 randomly selected medical malpractice lawsuits, it was found that 856 of them were dropped or dismissed (based on data from the Physicians Insurers Association of America). Test the claim that most medical malpractice lawsuits are drop

> In a KRC Research poll, 1002 adults were asked if they felt vulnerable to identity theft, and 53% of them said “yes.” Test the claim that the majority of adults feel vulnerable to identity theft.

> A Department of Health and Human Services study of illegal drug use among 12- to 17-year-olds reported a decrease in use (from 11.4% in 1997) to a current level of 9.9%. Suppose a survey in a large high school reveals that, in a random sample of 1050 stu

> Based on information from the National Cyber Security Alliance, 93% of computer owners believe that they have antivirus programs installed on their computers. In a random sample of 400 scanned computers, it is found that 380 of them (or 95%) actually hav

> To show how sugar production doubled from 1990 to now, an illustrator draws two sugar cubes. The first cube is drawn with a length of 1 cm on each side, and the second cube is drawn with a length of 2 cm on each side. What are the volumes of the two suga

> Listed below are the lengths (in minutes) of animated children’s movies. Construct a stem plot. Does the stem plot show the distribution of the data? If so, how? 83 88 120 64 69 71 76 74 75 76 75 75 79 80 78 78 83 77 71 83 80 73 72 82 74 84 90 89 81 81 9

> A study commissioned by the U.S. Department of Education, based on responses from 1015 randomly selected teenagers, concluded that 44% of teenagers cite grades as their greatest source of pressure. Test the claim that fewer than half of all teenagers in

> A survey showed that among 785 randomly selected subjects who completed four years of college, 144 smoke and the others do not smoke (based on data from the American Medical Association). Test the claim that the rate of smoking among those with four year

> A psychologist suspects that breathing exercises can help people with depression. To decide whether he is correct, he identifies a group of subjects, watches them do the breathing exercises, and then asks them how they feel afterward.

> In a 3M Privacy Filters poll, 806 adults were asked to identify their favorite seat when they fly, and 61% of them chose a window seat. Test the claim that the majority of adults prefer window seats when they fly.

> The claim p > 0.5 can never be supported if the sample proportion p̂ is less than 0.5.

> The area to the right of the standard score z = 1.0 is 0.1587, so the P-value in a two-tailed test is 0.1587.

> In a hypothesis test involving a claim made about a population proportion, if there is sufficient evidence to reject the null hypothesis, then there may or may not be sufficient evidence to support the alternative hypothesis.

> In a test of the claim that a majority of Americans believe that human activity is the major cause of global warming, the null hypothesis is p = 0.5 and the alternative hypothesis is p > 0.5.

> A survey of 61,647 people included several questions about office relationships. Of the respondents, 26% reported that bosses scream at employees. The survey was an Elle/MSNBC.com survey to which Internet users chose whether to respond. It is valid to us

> A P-value of 0.00001 is obtained when sample data are used to test the claim that the majority of car crashes occur within 5 miles of home. What does this P-value tell us?

> A newspaper used images of cigarettes of different sizes to depict the percentages of adults who smoke in 2000 and in 2017. Which graphic would depict these data more objectively: a bar graph or images of two cigarettes of different sizes? Why?

> What is a type I error? What is a type II error?

> What do we mean by critical values for significance in a hypothesis test for the population mean? How do we use critical values for making decisions about hypothesis tests?

> Consumer Reports rated house paints according to how well they hold up to hot weather by conducting an experiment in which they applied the various paints to identical surfaces that were then left exposed to the same hot weather conditions for the same l

> When testing a claim about a population mean, what is a standard score for the sample mean?

> Briefly describe what each of the variables n, x‾, s, σ , and μ represent in hypothesis tests of a claim made about a population mean.

> H0: The mean length of a bolt in the suspension system of new Audi cars is 3.456 centimeters. Ha: The mean length of a bolt in the suspension system of new Audi cars is not equal to 3.456 centimeters.

> H0: The lottery is fair. Ha: The lottery is biased.

> H0: The defendant is not guilty. Ha: The defendant is guilty.

> H0: The patient is free of a particular disease. Ha: The patient has the disease.

> In a survey conducted by Kelton Research, 1004 adults were asked to identify the sounds that they find most annoying. In response, 279 chose jackhammers, 388 chose car alarms, 128 chose barking dogs, and 209 chose crying babies. An illustrator depicts th

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. A simple random sample of 40 salaries of NCAA football coaches has a mean of $415,953. The standard devi

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. When 70 convicted embezzlers were randomly selected, the mean length of prison terms was found to be 22.

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. The health of the bear population in Yellowstone National Park is monitored by periodic measurements tak

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. The mean birth weight of male babies born to 121 mothers taking a vitamin supplement is 3.67 kilograms w

> I plan to use a double-blind experiment to test the hypothesis that people will experience a decrease in their pulse rate if they exercise vigorously for 40 minutes every day,

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. According to the U.S. Department of the Treasury, the mean weight of a quarter is 5.670 grams. A random

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. Researchers developed a questionnaire to identify compulsive buyers. A random sample of 32 subjects who

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. A random sample of 40 new baseballs is obtained. Each ball is dropped onto a concrete surface, and the b

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. According to the Energy Information Administration (Federal Highway Administration data), the average ga

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. A simple random sample of 50 adults is obtained, and each person’s red blood cell count (in cells per mi

> Weekly instruction time for a school student in the United States is 22.2 hours compared to 26.9 hours in China. Is the difference meaningful? How could a graph be constructed so that the difference is greatly exaggerated?

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. The label on the cold medicine Dozenol lists 600 milligrams of acetaminophen per fluid ounce as an activ

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. A clinical trial was conducted to test the effectiveness of the drug Zopiclone for treating insomnia in

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. A random sample of 36 cans of cola is obtained and the contents are measured. The sample mean is 12.19 o

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. According to a study by the Centers for Disease Control, the national mean hospital stay after childbirt

> Use a 0.05 significance level and conduct a full hypothesis test using the four-step process described in the text. Be sure to state your conclusion. A Roper poll used a sample of 100 randomly selected car owners. Within the sample, the mean time of owne

> What is blinding, and why is it important in an experiment that is testing the effectiveness of a drug?

> Assume that you are testing the alternative hypothesis Ha: µ< 4.43. If the sample mean has a standard score of z = 0.5, what do you conclude? Why is it not necessary to actually conduct a formal hypothesis test?

> Assume that you are testing the alternative hypothesis Ha: µ > 54.2. If the sample mean has a standard score of z = -1.0, what do you conclude? Why is it not necessary to actually conduct a formal hypothesis test?

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = 2.8 for H0: µ = 18.9 feet and Ha: µ > 18.9 fe

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = -0.9 for H0: µ = 612 feet and Ha: µ < 612 fee

> The rate of inflation in the 1970s was much higher than it is today, so prices today must be lower overall.

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = -1.7 for H0: µ = 36.9 degrees and Ha: µ ≠ 36

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = -2.7 for H0: µ = 120.5 kilograms and Ha: µ ≠

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = -2.1 for H0: µ = 24.7 miles and Ha: µ ≠ 24.7

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = -1.9 for H0: µ = 0.55 liter and Ha: µ ≠ 0.55

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = 2.1 for H0: µ = 232 pounds and Ha: µ ≠ 232 p

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = 1.7 for H0: µ = 125 pounds and Ha: µ ≠ 125 p

> What is a placebo, and why is it important in an experiment to test the effectiveness of a drug?

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = 1.5 for H0: µ = 15 centimeters and Ha: µ > 15

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = 3.0 for H0: µ = 15 centimeters and Ha: µ > 15

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = -3.0 for H0: µ = 15 centimeters and Ha: µ < 1

> There’s been only a very slight rise in our stock price over the past few months, but I wanted to make it look dramatic so I started the vertical scale from the lowest price rather than from zero.

> Use Table A-1 to find the P-value that corresponds to the given standard score, and determine whether to reject the null hypothesis at the 0.05 significance level. Is the alternative hypothesis supported? z = -1.5 for H0: µ = 15 centimeters and Ha: µ < 1

> Find the value of the standard scores, z, and determine whether to reject the null hypothesis at a 0.05 significance level. The critical values can be found in Tables 9.1 and 9.2. Is the alternative hypothesis supported? H0: µ = 75.0 seconds, Ha: µ ≠ 75

> Find the value of the standard scores, z, and determine whether to reject the null hypothesis at a 0.05 significance level. The critical values can be found in Tables 9.1 and 9.2. Is the alternative hypothesis supported? H0: µ= 25.5 g, Ha: µ≠  25.5 g, n

> Find the value of the standard score, z, and determine whether to reject the null hypothesis at a 0.05 significance level. The critical values can be found in Tables 9.1 and 9.2. Is the alternative hypothesis supported? H0: µ = 26.2 km Ha: µ ≠ 26.2 km,

> Find the value of the standard scores, z, and determine whether to reject the null hypothesis at a 0.05 significance level. The critical values can be found in Tables 9.1 and 9.2. Is the alternative hypothesis supported? H0: µ = 18.4 meters, Ha: µ  18.4

> Find the value of the standard scores, z, and determine whether to reject the null hypothesis at a 0.05 significance level. The critical values can be found in Tables 9.1 and 9.2. Is the alternative hypothesis supported? H0: µ = 52.2 kg, Ha: µ > 52.2 kg,

> Find the value of the standard scores, z, and determine whether to reject the null hypothesis at a 0.05 significance level. The critical values can be found in Tables 9.1 and 9.2. Is the alternative hypothesis supported? H0: µ = 20.5 seconds, Ha: µ < 20.

> In testing the effectiveness of a new vaccine, suppose that researchers used males for the treatment group and females for the placebo group. What is confounding, and how would it affect such an experiment?