# Question: Assume that the mean and the standard deviation of the

Assume that the mean and the standard deviation of the difference scores in Exercise 13.6 would remain the same if we added more subjects. How many subjects would we need to obtain a t that is significant at a 5 .01 (two-tailed)? (The difference was significant at a =.05, but no at a =.01.) (We will return to this general problem in Chapter 15.)

## Answer to relevant Questions

Modify the data in Exercise 13.6 by shifting the entries in the “12 hour” column so as to increase the relationship between the two variables. Run a t test on the modified data and notice the effect on t. (You could ...Use MYSTAT or LazStats to reproduce your result in Exercise 13.6. In Exercise 13.6. Hoaglin, Mosteller, and Tukey (1983) present data on blood levels of beta-endorphin as a function of stress. They took beta-endorphin levels ...We always need to look closely at our data. Sometimes we find things that are hard to explain. Look closely at the data in Exercise 13.6; what attracts your attention? Calculate Cohen’s d^ for the data in Exercise 14.15. Why can’t we use random assignment in the study of homophobia, and what effect will that have on the conclusions we are allowed to draw?Post your question