Exhibit 9-2 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes. The population standard deviation is known to be 0.5 minute. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. The test statistic is . a. .056 b. 1.96 x. 2.00 d. 1.64

c. 2.00

Step-by-step explanation:

The value of the test statistic is the value of t, given by

In which is the mean of our sample, is the mean we are testing, is the standard deviation of the sample and is the size of the sample.

In this problem, we have that:

So

So the correct answer is:

c. 2.00

answer: the answer is one of

step-by-step explanation:   we are given to write a proper fraction where the whole is divided into an even number of equal parts less than ten, and an odd number of those parts exist.

an even number less than 10 may be one of 2, 4, 6 or 8. so, the whole may be one of these four evens.

now, an odd number of these parts must exist, so the numerator must be an odd number, one of 1, 3, 5 or 7. it cannot be 9 because then the fraction will become improper.

thus, our fraction may be one of the following