A researcher begins with a known population in this case, scores on a standardized test that are normally distributed with = 65 and =15. The researcher suspects that special training in reading skills will produce a change in the scores for the individuals in the population. Because it is not feasible to administer the treatment (the special training) to everyone in the population, a sample of n=25 individuals is selected, and the treatment is given to this sample. Following treatment, the average score for this sample is M = 70. Is there evidence that the training has an effect on test scores?

 

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

b. Assuming a one-tailed test, state null hypothesis in a sentence that includes the independent variables and the dependent variable 

c. Using symbols, state the hypotheses (H0 and HI) for one-tailed test

d. Sketch appropriate distribution, and locate the critical region for alpha= 0.05

e Calculate the test statistic (z-score) for the sample if What decisions should be made about null hypothesis and what decision should be made about the effect of the program