Statistics Ch 11 Review

Chapter 11 Review Name ______________________________

1. The weights of three adult males are (in pounds) 160, 215, and 195. The standard error of the mean of these three weights is

A) 190.

B) 27.84.

C) 22.73.

D) 16.07.

2. The one sample t statistic from a sample of n = 19 observations for the two-sided test of

H0:  = 6

Ha:   6

has the value t = 1.93. Based on this information

A) we would reject the null hypothesis at  = 0.10.

B) 0.025 < P-value < 0.05.

C) we would reject the null hypothesis at  = 0.05.

D) both (b) and (c) are correct.

Use the following to answer questions 3-4:

Bags of a certain brand of tortilla chips claim to have a net weight of 14 ounces. Net weights actually vary slightly from bag to bag and are normally distributed with mean . A representative of a consumer advocate group wishes to see if there is any evidence that the mean net weight is less than advertised and so intends to test the hypotheses

H0:  = 14, Ha:  < 14

To do this, he selects 16 bags of this brand at random and determines the net weight of each. He finds the sample mean to be J = 13.88 and the sample standard deviation to be s = 0.24.

3. Based on the data above,

A) we would reject H0 at significance level 0.10 but not at 0.05.

B) we would reject H0 at significance level 0.05 but not at 0.025.

C) we would reject H0 at significance level 0.025 but not at 0.01.

D) we would reject H0 at significance level 0.01.

4. Referring to the information above, suppose we were not sure if the distribution of net weights was normal. In which of the following circumstances would we not be safe using a t procedure in this problem?

A) The mean and median of the data are nearly equal.

B) A histogram of the data shows moderate skewness.

C) A stemplot of the data has a large outlier.

D) The sample standard deviation is large.

5. Do students tend to improve their Math SAT (SAT-M) score the second time they take the test?...