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.

a. 0500 b. 0228 c. 0456 d. 0250

The correct option is B) 0.0228

Step-by-step explanation:

Consider the provided information.

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.

Thus, the value of n = 100, and σ = 0.5

We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes.

The null and alternative hypotheses are,

and

Compute the test statistic

By using the table.

P value = P(Z>2) = 0.0228

Hence, the correct option is B) 0.0228

7

step-by-step explanation:

the 8 in 8,420 is in the thousands place so it's value is 8 thousand.

the 8 in 6,870 is in the hundreds place so it's value is 8 hundred.

divide 8000 by 800 to find the answer:

8000 / 800 = 10

the 8 in 8,420 is 10 times greater than the 8 in 6,870