A researcher is investigating the effectiveness of a new study-skills training program for elementary school children. A sample of n=25 third-grade children is selected to participate in the program and each child is given a standardized achievement test at the end of the year. For the regular population of third-grade children, scores on the test form a normal distribution with a mean of u=150 and a standard deviation of o=25. The mean for the sample is M=158.
a. Identify the independent and the dependent variables for this study.
b. Assuming the two-tailed test, state the null hypothesis in a sentence that includes the independent variable and the dependent variable.
c. Using symbols, state the hypotheses (Ho & H1) for the two-tailed test.
d. Sketch the appropriate distribution, and locate the critical region for alpha = .05. (state the critical region, but you don't have to post the sketch unless you know how to input a graph)
e. Calculate the test statistic (z-score) for the sample. Show all steps, formulas, and plug in the numbers.