Question 1
ACME has 20 accountants. If the time it takes to complete the end of quarter report is normally distributed with a mean
of 30 hours and a standard deviation of 5 hours, the probability that it will take an accountant chosen at random less
than 27 hours is
.726
.0036
.274
.9964
Question 2
For the test of hypotheses:
Ho: mu <= 60
Ha: mu > 60
If you collect a sample of size 40 with a sample mean of 61 what would be the p-value assuming the population standard
deviation is 9?
.7589
.2411
.4558
.5442
Question 3
There are 500 bags of grain in the most recent shipment from Farm R Us. The weight of the bags are normally
distributed with a mean of 200 and a population standard deviation of 10 pounds. If you take a random sample of 20
bags, what is the probability that their average will be more than 201 pounds?
.540
.987
.013
.673
.327
.460
Question 4
The time it takes to complete the income tax forms is normally distributed with a mean of 10 hours with a standard
deviation of 2 hours. What is the probability that it will take more than 7 hours?
.001
.067
.999
.933
Question 5
It has been determined that the amount of time that it takes a manager to complete a simple clerical task has a mean of
400 minutes and a standard deviation of 70 minutes. If you collect a random sample of 50 managers, what is the
probability that their average will be more than 420 minutes?
Cannot determine since we do not know if the population is normally distributed.
.612
.978
.388
.022
Question 6
If a standardized test has scores that are normally distributed with a mean of 800 and a standard deviation of 100, how
high would you have to score to be in the upper 10th percentile?
928
668
1056
544
Question 7
Suppose a population has a population standard deviation of 50. What would be the upper limit of a 88 percent
confidence interval if you obtained a sample of size 60 that had a sample mean of 1000?
1010.0
1007.6
1058.7
1077.7
Question 8
For the test of hypotheses:
Ho: mu <= 50
Ha: mu > 50
If you collect a sample of size 60 with a sample mean of 52 what would be the p-value assuming the population standard
deviation is 10?
.9393
.4207
.0607
.5793
Question 9
For the test of hypotheses:
Ho: mu = 100
Ha: mu not equal to 100
If you collect a sample of size 64 with a sample mean of 104 what would be the p-value assuming the population
standard deviation is 20?
.5480
.1096
1.8904
.9452
Question 10
If you want to construct a 90 percent confidence interval that has a width of plus or minus 5, how large of a sample do
you need if the population standard deviation is 18?
34
137
55
8
Question 11
You are going to conduct a poll so that you can construct a 95 percent confidence interval with a margin of error of plus
or minus 6 percent. How many observations would you need to collect if you estimate that the population proportion is
approximately 80 percent?
246
582
171
231
Question 12
You are going to conduct a poll so that you can construct a 90 percent confidence interval with a margin of error of plus
or minus 7 percent. How many observations would you need to collect if you do not have a good idea of the value of the
population proportion?
325
139
196
84