MATH 3339 PREPARATION TEST 2026
QUESTIONS AND CORRECT ANSWERS
GRADED A+
● A potato chip company calculated that there is a mean of 75.4 broken
potato chips in each production run with a standard deviation of 5.2. If
the distribution is approximately normal, find the probability that there
will be fewer than 66 broken chips in a run. Answer: pnorm(66,75.4,5.2)
● A distribution of grades in an introductory statistics class (where A =
4, B = 3, etc) is:
x= 0,1,2,3,4
p(x)= 0.1,0.18,.22,.31,.19
find the mean and variance Answer: sum(x*p)
sum(x^2*p)-(sum(x*p)^2)
● The weights of male and female students in a class are summarized in
the following boxplots:
Which of the following is NOT correct? Answer: The male students
have less variability than the female students.
● P(A) = 0.31, P(B)=0.46 and P(AnB)=0.14, find P(AIB) Answer:
0.,14/0.46
, ● Identify the most appropriate test to use for the following situation:A
private and a public university are located in the same city. For the
private university, 1046 alumni were surveyed and 653 said that they
attended at least one class reunion. For the public university, 791 out of
1327 sampled alumni claimed they have attended at least one class
reunion. Is the difference in the sample proportions statistically
significant? Answer: Two sample z test for proportions
● A random sample of 121 cans of fruit nectar is drawn from among all
cans produced in a run. Prior experience has shown that the distribution
of the contents has a mean of 12.13 ounces and a standard deviation of
2.14 ounce. What is the probability that the average contents of the 121
sample cans is less than 11.81 ounces? Answer:
pnorm(11.81,12.13,2.14/sqrt(121))
● A random variable X has a probability distribution as follows:
X = 01234
P(X)= 7k 4k 2k 4k 4k
Find P(x<2) Answer: 7k+4k+2k+4k+4k=21k
k=1/21
P(0)+P(1)= 7k+4k = 11k
11(1/21)= 11/21
● Find a value of c so the P(z<c) = 0.71 Answer: qnorm(0.71)
QUESTIONS AND CORRECT ANSWERS
GRADED A+
● A potato chip company calculated that there is a mean of 75.4 broken
potato chips in each production run with a standard deviation of 5.2. If
the distribution is approximately normal, find the probability that there
will be fewer than 66 broken chips in a run. Answer: pnorm(66,75.4,5.2)
● A distribution of grades in an introductory statistics class (where A =
4, B = 3, etc) is:
x= 0,1,2,3,4
p(x)= 0.1,0.18,.22,.31,.19
find the mean and variance Answer: sum(x*p)
sum(x^2*p)-(sum(x*p)^2)
● The weights of male and female students in a class are summarized in
the following boxplots:
Which of the following is NOT correct? Answer: The male students
have less variability than the female students.
● P(A) = 0.31, P(B)=0.46 and P(AnB)=0.14, find P(AIB) Answer:
0.,14/0.46
, ● Identify the most appropriate test to use for the following situation:A
private and a public university are located in the same city. For the
private university, 1046 alumni were surveyed and 653 said that they
attended at least one class reunion. For the public university, 791 out of
1327 sampled alumni claimed they have attended at least one class
reunion. Is the difference in the sample proportions statistically
significant? Answer: Two sample z test for proportions
● A random sample of 121 cans of fruit nectar is drawn from among all
cans produced in a run. Prior experience has shown that the distribution
of the contents has a mean of 12.13 ounces and a standard deviation of
2.14 ounce. What is the probability that the average contents of the 121
sample cans is less than 11.81 ounces? Answer:
pnorm(11.81,12.13,2.14/sqrt(121))
● A random variable X has a probability distribution as follows:
X = 01234
P(X)= 7k 4k 2k 4k 4k
Find P(x<2) Answer: 7k+4k+2k+4k+4k=21k
k=1/21
P(0)+P(1)= 7k+4k = 11k
11(1/21)= 11/21
● Find a value of c so the P(z<c) = 0.71 Answer: qnorm(0.71)
