2. Assume a researcher wants to compare the
A) The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.22 and 39.78.
B) The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.33 and 39.67.
C) The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.32 and 39.68.
D) The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 29.43 and 44.57.
Trending nowThis is a popular solution!
Step by stepSolved in 3 steps with 2 images
- Research has shown that, for baseball players, good hip range of motion results in improved performance and decreased body stress. A research article reported on a study of independent samples of 40 professional pitchers and 40 professional position players. For the pitchers, the sample mean hip range of motion was 75.8 degrees and the sample standard deviation was 5.6 degrees, whereas the sample mean and sample standard deviation for position players were 79.9 degrees and 7.2 degrees, respectively. Assuming that the two samples are representative of professional baseball pitchers and position players, test hypotheses appropriate for determining if there is convincing evidence that the mean range of motion for pitchers is less than the mean for position players. (Use ? = 0.05. Use ?1 for pitchers and ?2 for position players.)arrow_forwardA custodian wishes to compare two competing floor waxes to decide which one is best. He believes that the mean of WaxWin is greater than the mean of WaxCo. In a random sample of 40 floors of WaxWin and 43 of WaxCo. WaxWin had a mean lifetime of 26.3 and WaxCo had a mean lifetime of 28. The population standard deviation for WaxWin is assumed to be 7.1 and the population standard deviation for WaxCo is assumed to be 6.1. Perform a hypothesis test using a significance level of 0.05 to help him decide. Let WaxWin be sample 1 and WaxCo be sample 2. The correct hypotheses are: O Ho: µ1 H2(claim) Ο H: μι μp HA: H1 < µ2(claim) O Ho: µ1 = 2 HA: μι μ (claim) Since the level of significance is 0.05 the critical value is 1.645 The test statistic is: (round to 3 places) The p-value is: (round to 3 places) The decision can be made to: O reject Ho O do not reject Ho The final conclusion is that: O There is enough evidence to reject the claim that the mean of WaxWin is greater than the mean of WaxCo.…arrow_forwardResearch has shown that, for baseball players, good hip range of motion results in improved performance and decreased body stress. A research article reported on a study of independent samples of 40 professional pitchers and 40 professional position players. For the pitchers, the sample mean hip range of motion was 75.5 degrees and the sample standard deviation was 5.8 degrees, whereas the sample mean and sample standard deviation for position players were 79.1 degrees and 7.1 degrees, respectively. Assuming that the two samples are representative of professional baseball pitchers and position players, test hypotheses appropriate for determining if there is convincing evidence that the mean range of motion for pitchers is less than the mean for position players. (Use ? = 0.05. Use ?1 for pitchers and ?2 for position players.) State the appropriate null and alternative hypotheses. Find the test statistic and P-value. (Use SALT. Round your test statistic to one decimal place and…arrow_forward
- A custodian wishes to compare two competing floor waxes to decide which one is best. He believes that the mean of WaxWin is not equal to the mean of WaxCo.In a random sample of 49 floors of WaxWin and 35 of WaxCo. WaxWin had a mean lifetime of 25.3 and WaxCo had a mean lifetime of 27.3.The population standard deviation for WaxWin is assumed to be 7.8 and the population standard deviation for WaxCo is assumed to be 10.2.Perform a hypothesis test using a significance level of 0.05 to help him decide.Let WaxWin be sample 1 and WaxCo be sample 2.arrow_forwardAn important measure in the study of contagious infectious diseases is the number of cases directly generated by one previous case. Jessica is an epidemiologist studying the spread of an infectious disease in her country. She claimed that the mean number of cases directly generated by one previous case is now greater than 1.2. A study of 12 randomly selected cases of the disease is conducted and finds the sample mean number of cases directly generated by one previous case to be 1.5 with a sample standard deviation of 0.7. Assume that the population of the number of cases directly generated by one previous case is approximately normally distributed. Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.10 level of significance, to support the claim that u, the mean number of cases directly generated by one previous case, is greater than 1.2. (a) State the null hypothesis H, and the alternative hypothesis H, that you would use for the test.…arrow_forward3. At a land farm, a farmer desired to test the effect of a given fertilizer on soybean production. He chose 24 plots of land of which are equal surface area. He treated 12 plots with the fertilizer and the others were untreated. Otherwise the conditions were the same. The treated plots produced soybean with mean yield 5.1 bushels and a standard deviation of 0.36 bushels, while the untreated plots had mean yield 4.8 bushels and a standard deviation of 0.40 bushels. (a) Can we conclude that there is a significant improvement in soybean production because of the fertilizer if a significance level of 1% is used? (b) What is the P-value of the test?arrow_forward
- A new drug is being tested to see if it reduces the frequency of migraines. Study participants were divided into two groups. 49 participants in group 1 received the medication; 42 participants in group 2 received a placebo. After a period of six months, group 1 had a mean of 4 migraines. It is known that the population standard deviation for this group is 1.3 migraines. Group 2 had a mean of 5.4 migraines. The population standard deviation for this group is 1.7 migraines. Can we conclude that the medication reduces the population mean number of migraines? Use αα =0.01. Note: If t-test, then unequal variances are assumed. Question a)Let: μ1μ1 = the population mean number of migraines with the medication μ2μ2 = the population mean number of migraines with the placebo (Step 1) State the null and alternative hypotheses by selecting the appropriate symbol, and identify which tailed test: H0:H0: μ1μ1 μ2μ2 H1:H1: μ1μ1 μ2μ2 Which tailed test…arrow_forwardFran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2. Step 2 of 3 : Compute the value of the test statistic. Round your answer to two decimal places.arrow_forwardA sample of 76 female workers and another sample of 48 male workers from a state produced mean weekly earnings of $743.50 for the females and $777.63 for the males. Suppose that the population standard deviations of the weekly earnings are $80.05 for the females and $88.68 for the males. The null hypothesis is that the mean weekly earnings are the same for females and males, while the alternative hypothesis is that the mean weekly earnings for females is less than the mean weekly earnings for males. Directions: • Label your answers with the correct statistical symbols. • If you use the Ti, identify which function and values you used to calculate. If you solve by hand, show all steps 2.5 The significance level for the test is 1%. What is/are the critical value(s)? 2.6. What is the value of the test statistic, rounded to three decimal places? 2.7. What is the p-value for this test, rounded to four decimal places? 2. 8. Using the p-value approach, do you reject or fail to reject the null…arrow_forward
- A new small business wants to know if its current radio advertising is effective. The owners decide to look at the mean number of customers who make a purchase in the store on days immediately following days when the radio ads are played as compared to the mean for those days following days when no radio advertisements are played. They found that for 10 days following no advertisements, the mean was 18.3 purchasing customers with a standard deviation of 1.8 customers. On 7 days following advertising, the mean was 19.4 purchasing customers with a standard deviation of 1.6 customers. Test the claim, at the 0.02 level, that the mean number of customers who make a purchase in the store is lower for days following no advertising compared to days following advertising. Assume that both populations are approximately normal and that the population variances are equal. Let days following no advertisements be Population 1 and let days following advertising be Population 2. Step 3 of 3: Draw a…arrow_forwardA personnel psychologist has to decide which of three employees to place in a particular job that requires a high level of coordination. All three employees have taken tests of coordination, but each took a different test. Employee A scored 15 on a test with a mean of 10 and a standard deviation of 2; Employee B scored 350 on a test with a mean of 300 and a standard deviation of 40; and Employee C scored 108 on a test with a mean of 100 and a standard deviation of 16. (On all three tests, higher scores mean greater coordination.) Which employee has the best coordination? (hint: convert raw scores to z scores and compare) Select one: a. Employee A b. Employee B c. Employee C Clear my choicearrow_forwardA new small business wants to know if its current radio advertising is effective. The owners decide to look at the mean number of customers who make a purchase in the store on days immediately following days when the radio ads are played as compared to the mean for those days following days when no radio advertisements are played. They found that for 7 days following no advertisements, the mean was 22.1 purchasing customers with a standard deviation of 1.2 customers. On 10 days following advertising, the mean was 24.1 purchasing customers with a standard deviation of 1.6 customers. Test the claim, at the 0.05 level, that the mean number of customers who make a purchase in the store is lower for days following no advertising compared to days following advertising. Assume that both populations are approximately normal and that the population variances are equal. Let days following no advertisements be Population 1 and let days following advertising be Population 2. Step 1 of 3: State the…arrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman