A medical researcher wants to test the claim that healthy adults have a mean body temperature of 98.6°F.
> 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?
> 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 = 3.8 cm, Ha: µ < 3.8 cm, n
> 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 = 5.50 grams, Ha: µ > 5.50
> I used an exponential scale because the data values for my categories ranged from 7 to 450,000,000.
> A handy mnemonic for interpreting the P-value in a hypothesis test is this: “If the P (value) is low, then the null must go.”
> Because the significance level is the probability of making a type I error, it is wise to select a significance level of zero so that there is no chance of making that error.
> When a consumer group is testing the claim that the mean amount of aspirin in tablets is 350 milligrams, it is extremely important not to wrongly reject a true null hypothesis. Thus, it is better to choose 0.01 than 0.05 for the significance level.
> A significance level of 0.05 indicates that the probability of making a type I error is 0.05.
> The principal claimed that the school’s mean SAT score was above 650. A hypothesis test seemed to back her up, but it later turned out that the mean score was exactly 650. Therefore, the test resulted in a type I error of wrongly rejecting the null hypo
> In testing a claim about a population mean, if the standard score for a sample mean is z = 0, then there is not sufficient sample evidence to support the alternative hypothesis.
> When conducting hypothesis tests, you need to consider a different set of critical values for two-tailed tests than for one-tailed tests.
> What is a P-value for a hypothesis?
> Define variable, variables of interest, explanatory variable, and response variable. How are the explanatory and response variables related to each other?
> What are the two possible outcomes of a hypothesis test, and what do they mean? Can such a test have an outcome of accepting the null hypothesis?
> I drew a map on which I scaled the lengths (from east to west) of different counties based on their numbers of family-owned farms, and found that a county with twice as many farms as another ended up looking four times as large.
> What is a null hypothesis and an alternative hypothesis, and what notation do we use to denote them? How do left-tailed, right-tailed, and two-tailed hypothesis tests differ?
> What is a hypothesis in statistics? What do we mean by a hypothesis test in statistics?
> A random sample of 100 births includes 35 male babies. Is this result significant at the 0.05 level? What is the P-value for this result? What would you conclude based on this result? Answer: Yes. The P-value of 0.002 is less than the significance level
> A random sample of 100 births includes 35 male babies. Is this result significant at the 0.01 level? What is the P-value for this result?
> A random sample of 100 births includes 40 male babies. Is this result significant at the 0.05 level? What is the P-value for this result?
> A random sample of 100 births includes 40 male babies. Is this result significant at the 0.01 level? What is the P-value for this result?
> A random sample of 100 births includes 45 male babies. Is this result significant at the 0.01 level? What is the P-value for this result?
> A random sample of 100 births includes 48 male babies. Is this result significant at the 0.05 level? What is the P-value for this result?
> A bookstore owner claims that the proportion of people who read books in print is greater than 0.25.
> What is a biased sample, and what is a major problem with it?
> You want to determine the percentage of people in this country with each of the four major blood types (A, B, AB, and O). What would be an effective sampling plan that accounts for differences among ethnic groups?
> A bookstore owner claims that the proportion of people who read books in print is not 0.23.
> A sales representative claim that quarters inserted into her vending machines have a mean weight less than 5.64 grams.
> A sales representative claims that quarters inserted into her vending machines have a mean weight of 5.64 grams.
> The quality control manager at a manufacturing company claims that the proportion of defective transistors is 0.03.
> The quality control manager at a manufacturing company claims that the proportion of defective transistors is greater than 0.03.
> A medical researcher wants to test the claim that healthy adults have a mean body temperature less than 98.6°F.
> In testing a method of gender selection, 200 couples use a treatment designed to increase the likelihood of having a girl, and each couple has one baby. Answer the following questions without doing any calculations. a. If the 200 babies include exactly
> In testing a method of gender selection, 40 couples use a treatment designed to increase the likelihood of having a girl, and each couple has one baby. Answer the following questions without doing any calculations. a. If the 40 babies include exactly 22
> When interpreting a P-value of 0.009, a researcher states that the results are statistically significant because the P-value is very small, indicating that the results are not likely to occur by chance.
> What are geographical data? Identify at least two ways to display geographical data.
> What is a representative sample, and why is it important?
> The producer of a new song surveys 1000 consumers and finds that most of them are very enthusiastic about it, so she convinces the Sony recording company to promote the song.
> When interpreting a P-value of 0.45, a researcher states that the results are statistically significant because the P-value is less than 0.5, indicating that the results are not likely to occur by chance.
> A study is designed to determine the proportion of men who weigh more than 195 pounds, so the null hypothesis is µ = 195 pounds and the alternative hypothesis is µ > 195 pounds.
> In a test of the claim that, among patients treated with Ziac, the proportion who experience dizziness is less than 0.06, the null hypothesis is p < 0.06.
> After conducting a hypothesis test, I found that my result was statistically significant at the 0.05 level and had a P-value of 0.3.
> The results of my hypothesis test were statistically significant at the 0.01 level, so no one can doubt my claim any longer.
> A researcher conducts a hypothesis test to test the claim that a new drug is effective in lowering LDL cholesterol. The P-value for the test is 0.001, and the researcher claims that this supports the claim.
> To learn about smart phone ownership, I chose a null hypothesis claiming that the proportion of adults who own a smart phone is equal to 0.8, and the result of my hypothesis test proved this claim to be true.
> Our survey found that 56% of voters approve of a particular policy of the President, with a margin of error (for 95% confidence) of 4 percentage points. Therefore, there is only a 5% chance that the proportion of approval among all voters differs from 56
> Briefly describe how each of the following can be used to show multiple data sets: a multiple bar graph, a multiple line chart, and a stack plot. When is the stack plot most useful?
> Construct a stem plot of these test scores: 67, 72, 85, 75, 89, 89, 88, 90, 99, and 100. How does the stem plot show the distribution of these data?
> How can you determine an appropriate sample size for a study if you want a particular margin of error?
> Once you have constructed the 95% confidence interval around your sample proportion, what does this tell you about the estimated value of the population proportion?
> What is a census, what is a sample, and what is the difference between them?
> If you seek to construct a 95% confidence interval around your sample proportion, how do you calculate the margin of error that you will use? How do you then construct the 95% confidence interval?
> Suppose you conducted an opinion poll and measured the proportion of your sample that held a particular view. What value should you use as your estimate of the population proportion?
> Two thirds (or 66.6%) of 626 Colorado residents polled by Talmey Drake Research & Strategy Inc. said that they backed a bill pending in the legislature that would standardize laws on granting concealed weapon permits to gun owners. The bill would force l
> A poll finds that 54% of the population approves of the job that the President is doing; the poll has a margin of error of 4% (assuming a 95% confidence level). a. What is the 95% confidence interval for the true population percentage that approves of th
> The Bureau of Labor Statistics estimates the unemployment rate in the United States each month by surveying 60,000 individuals. a. In one month, 3.4% of the 60,000 individuals surveyed are found to be unemployed. Find the margin of error for this estimat
> Prior to a statewide election for the U.S. Senate, three polls are conducted. In the first poll, 780 of 1500 voters favor candidate Martinez. In the second poll, 1285 of 2500 voters favor Martinez. In the third poll, 1802 of 3500 voters favor Martinez. F
> The drug Eliquis is used to help prevent blood clots in certain patients. In clinical trials, among 5924 patients treated with Eliquis, 153 developed the adverse reaction of nausea (based on data from BristolMyers Squibb Co.). Construct a 95% confidence
> The following table lists labor force participation rates (as percentages) of mothers, categorized according to the age of their youngest child (based on data from the Bureau of Labor Statistics).
> A study by Stanford University researchers for the Office of National Drug Control Policy and the Department of Health and Human Services concluded that 98% of the top rental films involve drugs, drinking, or smoking. Assume that this study is based on t
> A Pew Research Center poll surveyed 1708 randomly selected adults who were asked whether “global warming is a problem that requires immediate government action.” Results showed that 939 of those surveyed indicated that immediate government action is requ
> The Genetics and IVF Institute conducted clinical trials of the YSORT method designed to increase the probability of conceiving a boy. Among 152 babies born to parents using the YSORT method, 127 were boys. Calculate the margin of error and the 95% confi
> In a Gallup poll of 1059 adults, the interview subjects were selected by using a computer to randomly generate telephone numbers (both land lines and cell phones) that were then called.
> In a study of the accuracy of order filling at fast food drive through, McDonald’s had 33 orders that were not accurately filled among 362 orders observed (based on data from QSR magazine). Calculate the margin of error and the 95% confidence interval fo
> A study done by researchers at Alfred University concluded that 80% of all student athletes in this country have been subjected to some form of hazing. The study is based on responses from 1400 athletes. What is the margin of error and the 95% confidence
> Repeat Exercise 21 assuming that the sample size is doubled to 10,000. Given that the large cost and effort of conducting the Nielsen survey would be doubled, does this increase in sample size appear to be justified by the increased reliability?
> Nielsen Media Research uses samples of 5000 households to rank TV shows. Nielsen reported that 60 Minutes had 15% of the TV audience. What is the 95% confidence interval for this result?
> Assume that you want to construct a 95% confidence interval to estimate a population mean. Find the minimum sample size needed to obtain the specified margin of error for the 95% confidence interval. E = 0.015
> Assume that you want to construct a 95% confidence interval to estimate a population mean. Find the minimum sample size needed to obtain the specified margin of error for the 95% confidence interval. E = 0.123
> The following table summarizes deaths due to firearms in different nations in a recent year (data from the Coalition to Stop Gun Violence).
> Assume that you want to construct a 95% confidence interval to estimate a population mean. Find the minimum sample size needed to obtain the specified margin of error for the 95% confidence interval. E = 0.025
> Assume that you want to construct a 95% confidence interval to estimate a population mean. Find the minimum sample size needed to obtain the specified margin of error for the 95% confidence interval. E = 0.03
> Assume that population proportions are to be estimated from the samples described. In each case, find the approximate margin of error and 95% confidence interval. n = 2250, p̂ = 0.853
> Assume that population proportions are to be estimated from the samples described. In each case, find the approximate margin of error and 95% confidence interval. n = 420, p̂ = 0.65
> A college dean obtains an alphabetical list of all full-time students at her college and she selects every 50th name on that list and interviews those students to find the amount of student debt incurred by each of them. She uses the results to estimate
> Assume that population proportions are to be estimated from the samples described. In each case, find the approximate margin of error and 95% confidence interval. Sample size, n = 1260; sample proportion, p̂ = 0.25
> Assume that population proportions are to be estimated from the samples described. In each case, find the approximate margin of error and 95% confidence interval. Sample size, n = 555; sample proportion, p̂ = 0.8
> In a Pew Research Center poll, 73% of 3011 adults surveyed said that they use the Internet. In this context, what are n, p ̂, and p?
> Here is a typical statement made by the media: “Based on a survey of 1068 likely voters, 56% favor the proposed environmental legislation, and this survey has a margin of error of 3 percentage points.” What important and relevant piece of information is
> In a study of 1228 randomly selected medical malpractice lawsuits, it is found that the proportion that were dropped or dismissed is 0.697. When a 95% confidence interval is constructed for the population proportion of all lawsuits, the margin of error i
> The following table gives the number of daily newspapers and their total circulation (in millions) for selected years since 1920 (from Editor& Publisher).
> The Journal of the American Medical Association published an article about a survey of adults and cited this 95% confidence interval for the proportion of adults who use at least one prescription medication: 0.803 < ρ < 0.831. Interpret that confidence i
