10.25 Females or males more nicotine dependent? Refer to Exercise 10.23 about studying nicotine dependence using a random sample of teenagers. Of those seventh graders in the study who had tried tobacco, the mean HONC score was 2.8 1s = 3.62 for the 150 females and 1.6 1s = 2.92 for the 182 males.

a. Find a standard error for comparing the sample means.

Interpret.

b. Find the test statistic and P-value for H0: m1 = m2 against Ha: m1 • m2. Interpret and explain what (if any) effect gender has on the mean HONC score.

c. Do you think that the HONC scores were approximately normal for each gender? Why or why not?

How does this affect the validity of the analysis in part b?