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Frequency distribution, sampling Distribution, chi-square

1. Consider the following stem and leaf plot:
Stem Leaf
1 0,2,5,7
2 2,3,4,8
3 0,4,6, 6, 9
4 5,8,8,9
5 2,7, 8

Suppose that a frequency distribution was developed from this, and there were 5 classes (10-under 20, 20-under 30, etc.). What is the cumulative frequency for the 30-under 40 class interval?

a) 13
b) 9
c) 5
d) 14

2. Increasing the sample size causes the sampling distribution of to ________.
a) shift to the right
b) have less dispersion
c) shift to the left
d) have more dispersion

3. David Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks. Based on a recent census of personnel, David knows that the variance of teller training time in the Southeast region is 8, and he wonders if the variance in the Southwest region is the same number. His staff randomly selected personnel files for 15 tellers in the Southwest Region, and determined that their mean training time was 25 hours and that the standard deviation was 4 hours. Using &#945; = 0.10, the critical values of chi-square are ________.

a) -1.96 and 1.96
b) 7.96 and 26.30
c) 6.57 and 23.68
d) -1.645 and 1.645

Solution Preview

1. Consider the following stem and leaf plot:
Stem Leaf
1 0,2,5,7
2 2,3,4,8
3 0,4,6, 6, 9
4 5,8,8,9
5 2,7, 8

Suppose that a frequency distribution was developed from this, and there were 5 classes (10-under 20, 20-under 30, etc.). What is the cumulative frequency for the 30-under 40 class interval?

a) 13
b) 9
c) 5
d) 14