2. Researchers are interested in determining if method of studying is associated with test scores (possible test scores range from 0-15). A class with 12 students is split into four groups with different studying instructions, Group A, B, C, and D. Each group has 3 students. The data is below. The researchers are going to run a statistical test to determine if the mean score on the test is the same for each study method or not, using alpha=5%.
Group A 12 11 12
Group B 7 8 6
Group C 5 8 7
Group D 7 8 8
a. Which statistical test should they run? Explain your answer.
b. Write the null and alternative hypotheses in words and symbols/notation. Are you using a one-sided or two-sided alternative hypothesis?
c. Calculate the test statistic.
d. Determine the critical / threshold t-value for alpha=5%
e. What is the p-value, and what decision should the researcher make?
f. What error could the researcher have made (type 1 or type 2), given the context and the result you just found? Name it and describe in context.