Ch 10.1 Practice Worksheet

docx

School

West Texas A&M University *

*We aren’t endorsed by this school

Course

1324

Subject

Statistics

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by kylee1015

Chapter 10.1 Practice Worksheet 1. Do WT business students differ in motivation from Texas Tech students? A randomly selected group of each were administered the Sarnoff Survey of Attitudes toward Life (SSATL), which measures motivation for upward mobility. Give the null and alternative hypotheses to determine if the mean SSATL score of WT students differs from the mean SSATL score of Texas Tech students H0: µWT = µTT H1: µWT ≠ µ TT Suppose that we run an independent samples t test to test these hypotheses at a .01 significance level. The critical values for this test is t = +/- 2.33. The test statistic for the difference between the sample means is t=-3.69. What can we conclude? We can conclude there is sufficient evidence that the motivation between WT and TT students is not the same 2. Double Bubble bubble gum wants to come up with a gum with flavor that lasts for more than 5 seconds. They develop a new recipe and compare the time it takes to lose flavor with the time of the original recipe. He randomly selects 100 pieces from each recipe. The manufacturer believes that the differences are normally distributed and will use these samples to perform an appropriate test at a level of significance of 0.01. The p-value of the test statistic is .082. Should Double Bubble switch recipes? Why? H0: µ1 = µ2 H1: µ1 ≠ µ2 No, there is insufficient evidence that there is a difference in the flavors 3. The p-value refers to the probability of a type 1 error… but what does this mean for a 2 samples t-test? this means the probability that we would get this observed difference between the two groups given that they are the same is so extremely low that we are going to assume that the two groups aren’t the same. 4. Suppose AT&T wants to know if there is a difference in the proportion of males and females who use AT&T. They take a convenience sample and find that 56 of 105 men and 43 of 95 women have AT&T. H0: proportionM = proportionF H1: proportionM ≠ proportionF They develop a 95% confidence interval for the differences and find it to be [-.09, .10] What should our decision be?

Do not reject H0, the confidence interval contains 0, meaning that it is possible that there is no difference between the two proportions 5. Dr. C wants to know if there is a difference in the average weight gain after Thanksgiving among her 3 classes. What test do we have to use? ANOVA Write the null and alternative hypotheses H0: µ1 = µ2 = µ3 H1: at least one of the averages is different Dr. C randomly samples 15 students from each class, records weight gain, and finds the following: Class 1 mean = 1.53lb Class 2 mean = 2.6lb Class 3 mean = 1.28lb She runs an ANOVA at a level of significance of .05 (F critical value = 6.07). The F statistic is = 8.22. P value = .000974 What can we conclude? There is sufficient evidence to conclude that the groups are not the same

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version