STATSTISTICS

QUESTION 1

1. Fill in the blanks for "x" and "z". A medical database has over 10,000 health records. The data was recently transferred from written records. The administrator wants to assess how often errors or omissions occurred in the transfer process. She randomly selects 16 health records and finds that these average 17 omissions or errors each. The sample standard deviation is 2.5. Find the 90% confidence interval (α=0.10) for the average number of omissions or errors per record in the overall database rounding to tenths : _____≤ μ ≤ _____.

8 points   

QUESTION 2

1. Fill in the blanks for "x" and "y". ) A bulk supply of CAT6 cables were purchased to implement a wired office network. The network designer randomly tests 12 of the cables and finds the attenuation is on average 22.7dB with a sample standard deviation of 1.9 dB. She wishes to estimate the 95% confidence interval for the mean attenuation of all of the cables. Find the 95% confidence interval (α=0.05) for the mean attenuation rounded to the nearest tenth: _  ____dB≤ μ ≤ __  ___dB.

8 points   

QUESTION 3

1. What is the t-statistic used in a 90% confidence interval calculation for a sample size of 9?

2 points   

QUESTION 4

1. Match each the following statistics to the appropriate test:

ratio of variances for two samples                                                    difference of two sample means                                                    variance compared to a predicted population variance                                                    mean compared to predicted sample mean with known population variance

a. z-test b. χ2-test c. t-test d. F-test

4 points   

QUESTION 5

1. For a 85% confidence interval, what is the value of α?

2 points   

QUESTION 6

1. Find the test statistics using the tables in the text. χ2(10,0.05)

2 points   

QUESTION 7

1. Find the test statistics using the tables in the text. z(0.05)

2 points   

QUESTION 8

1. Find the test statistics using the tables in the text. F(7,11,.05)

2 points   

QUESTION 9

1. Find the test statistics using the tables in the text. t(10,0.05)