ISDS 361A LATEST 2026 EXAM QUESTIONS AND SOLUTIONS RATED A.pdf

ISDS 361A LATEST 2026 EXAM QUESTIONS AND
SOLUTIONS RATED A+
✔✔What is the probability that a random sample of 36 supermarkets will provide an
average milk price (X¯) that is more than $3.50?
Select one:

a. 4.5%
b. 9%
c. 31%
d. 45.5% - ✔✔n 36
mean 3
sigma 1.75
x bar 3.5
Z 1.714286
SE 0.291667
P(X>3.5) 4.5%

Z = X bar - mean/SE
SE= Sigma/sqrt(n)
P(X>3.5) = 1-NORM.S.DIST(1.7,TRUE)

a. 4.5%

✔✔What is the probability that a random sample of 36 supermarkets will provide an
average milk price (X¯) that is within $0.50 of the population mean (μ)?
Select one:

a. 62%
b. 38%
c. 91%
d. 9% - ✔✔n 36
mean 3
sigma 1.75
x1 bar 3.5
z 1.714286
SE 0.291667

n 36
mean 3
sigma 1.75
x2 bar 2.5
z -1.71429

P(2.5>X>3.5) 91.1%
Z = X bar - mean/SE

, SE= Sigma/sqrt(n)
P(2.5>X>3.5) = NORM.S.DIST(1.7,TRUE)-NORM.S.DIST(-1.7,TRUE)

c. 91%

✔✔The probability in the PREVIOUS question would _________if we were to increase
the sample size to 72.
Select one:

a. decrease
b. stay the same
c. increase
d. be zero - ✔✔n 72
mean 3
sigma 1.75
x1 bar 3.5
Z 2.424366
SE 0.206239

n 72
mean 3
sigma 1.75
x2 bar 1.75
Z -2.42437
SE 0.206239

P(2.5>X>3.5) 98.4%

c. increase

✔✔Use this information to answer the following 6 questions::
The U.S. Police department wants to know if a new campaign, to make citizens aware
of the dangers of drunk driving, has been effective. They count the number of drivers
who have been stopped with more alcohol in their body than the law permits for each
day of the week in the week before and the week a month after the campaign starts.
The results are in this data link:
Day of Week After Before
M16
T83
W68
Th 2 9
F06
S 2 15
Su 7 9