QUESTION 1

The Iowa Department of Transportation repaired hundreds of bridges in 1993. To check the average cost to repair a bridge, a random sample of n = 55 bridges was chosen. The mean and standard deviation for the sample are $25,788 and $1,540, respectively. Records from previous years indicate an average bridge repair cost was $25,003. Use the sample data to test that the 1993 mean is greater than $25,003. Use alpha = 0.05.

What is the test statistic? ----------

QUESTION 2

The Iowa Department of Transportation repaired hundreds of bridges in 1993. To check the average cost to repair a bridge, a random sample ofn= 55 bridges was chosen. The mean and standard deviation for the sample are $25,788 and $1,540, respectively. Records from previous years indicate an average bridge repair cost was $25,003. Use the sample data to test that the 1993 meanis greater than $25,003. Use alpha = 0.05.

What is the critical value?

QUESTION 3

An insurance company wants to test the hypothesis that the mean amount of life insurance held by professional men equals that held by professional women. Accordingly, two independent simple random samples are taken from appropriate professional listings of men and women. The sample of 200 men reveals a mean amount of $140,000 with a standard deviation $26,000. The sample of 400 women shows a mean amount of $128,000 with a standard deviation of $3,000. Test the hypothesis using an alpha = 0.05 significance level.

What is the test statistic?

QUESTION 4

An insurance company wants to test the hypothesis that the mean amount of life insurance held by professional men equals that held by professional women. Accordingly, two independent simple random samples are taken from appropriate professional listings of men and women. The sample of 200 men reveals a mean amount of $140,000 with a standard deviation $26,000. The sample of 400 women shows a mean amount of $128,000 with a standard deviation of $3,000. Test the hypothesis using analpha = 0.05 significance level.

What is the conclusion?

a.	Reject Ho
b.	Do not reject Ho

QUESTION 5

In clinical studies of an allergy drug, 81 of the 900 subjects experienced drowsiness. A competitor claims that 10% of the users of this drug experience drowsiness. At the 5% significance level, what is the test statistic?

QUESTION 6

In clinical studies of an allergy drug, 81 of the 900 subjects experienced drowsiness. A competitor claims that 10% of the users of this drug experience drowsiness. At the 5% significance level, what is the conclusion?

a.	reject Ho
b.	do not reject Ho

QUESTION 7

Independent random samples of n₁ = 150 and n₂ = 150 sales phone calls for an insurance policy were randomly selected from binomial populations 1 and 2, respectively. Sample 1 had 80 successful sales, and sample 2 had 88 successful sales. Suppose you have no preconceived theory concerning which parameter, p₁ or p₂, is the larger and you wish to detect only a difference between the two parameters if one exists.

What is the test statistic?

QUESTION 8

Independent random samples ofn₁= 150 andn₂= 150 sales phone calls for an insurance policy were randomly selected from binomial populations 1 and 2, respectively. Sample 1 had 80 successful sales, and sample 2 had 88 successful sales. Suppose you have no preconceived theory concerning which parameter,p₁orp₂, is the larger and you wish to detect only a difference between the two parameters if one exists.

What is the conclusion at alpha = 0.05?

a.	reject Ho
b.	do not reject Ho

QUESTION 9

Suppose that a response can fall into one of k = 5 categories with equal probability, and that n = 250 responses produced these category counts:

category: 1 2 3 4 5

observation: 39 53 61 43 54

Perform a goodness of fit test to see if all the categories are equally likely to occur.

What is the test statististic?

QUESTION 10

Suppose that a response can fall into one ofk= 5 categories with equal probability, and thatn= 250 responses produced these category counts:

category: 1 2 3 4 5

observation: 39 53 61 43 54

Perform a goodness of fit test to see if all the categories are equally likely to occur.

What is the critical value with alpha = 0.05?