Question

A recent study evaluated how addicted teenagers become to nicotine once they start smoking. The response variable was the number of yes answers on a questionnaire called the Hooked on Nicotine Checklist​ (HONC). Of teenagers who had tried​ tobacco, the mean HONC score was 2.9 ​(s=4.3​) for the 150 females and 2.3 (s=3.6​) for the 181 males. Complete parts a through c below.

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

What does the standard error​ indicate?

A.The standard error describes the spread of the sampling distribution of x1−x2.

B.The standard error is the standard deviation of the difference between x1−x2.

C.The standard error is the difference in standard deviations for the two populations.

D.The standard error is the standard deviation of the sample for this study.

b. Find the test statistic and​ P-value for H0​ and Ha​

​Interpret, and explain what​ (if any) effect gender has on the mean HONC score. Use the significance level 0.050

The test statistic is ? (Round to 2 decimal places)

P value is?

Since the​ P-value is --- than 0.050 ---- the null hypothesis. Conclude that the mean HONC for females ----- the mean HONC score for males.

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?

Do you think the scores for females were approximately​ normal?

A. The sample mean is less than 1 standard deviation above the lowest possible​ score, 0, so the population cannot be approximately normal.

B.The sample mean is more than 3 standard deviations above the lowest possible​ score, 0, so the population could be approximately normal.

C.The sample size is greater than​ 30, so the population is approximately normal.

D.The sample size is greater than​ 30, so the population is not approximately normal.

Do you think the scores for males were approximately​ normal?

A.The sample size is greater than​ 30, so the population is not approximately normal.

B.The sample mean is more than 3 standard deviations above the lowest possible​ score, 0, so the population could be approximately normal.

C.The sample size is greater than​ 30, so the population is approximately normal.

D.The sample mean is less than 1 standard deviation above the lowest possible​ score, 0, so the population cannot be approximately normal.

Does this affect the validity of the​ analysis?

A.This affects the validity of the analysis because the populations must be approximately normal.

B.This affects the validity of the analysis because the sample sizes are small.

C.This does not affect the validity of the analysis since the populations are approximately normal.

D.This does not affect the validity of the analysis since the sample sizes are large.

Answer 1

Since the​ P-value is greater than 0.05, fail to reject the null hypothesis. Conclude that the mean HONC for females is significantly different than the mean HONC score for males.

(c) The sample size is greater than​ 30, so the population is approximately normal.
The sample size is greater than​ 30, so the population is approximately normal.
This does not affect the validity of the analysis since the populations are approximately normal.