# Question #2013547: Z-test: Testing hypotheses

Question: 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 $$\sigma$$ =25. The mean is M=158.

a. Identify the independent and the dependent variables for this study

b. assuming a 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 a=.05.

e. Calculate the test statistic (z score) for the sample