Question 1
In a certain region, the mean annual salary for plumbers is $51,000. Let x be a random variable that represents a plumber's salary. Assume the standard deviation is $1300. If a random sample of 100 plumbers is selected, what is the probability that the sample mean is greater than $51,300?
|
A.
|
0.32
|
|
B.
|
0.03
|
|
C.
|
0.41
|
|
D.
|
0.01
|
Question 2
The braking distances of a Honda CRV can be approximated by a normal distribution, where the mean is 53 meters and the standard deviation is 3.8 meters. Let x be a random variable that represents a braking distance. Find the probability that a randomly selected braking distance is less than 49 meters.
Question 3
A 6-sided die is rolled once. Find the probability of rolling a number less than 3 or rolling an odd number.
|
A.
|
5/6
|
|
B.
|
4/6
|
|
C.
|
3/6
|
|
D.
|
1
|
Question 4
A automobile race contains 15 racecars. In how many ways can the racecars finish in first, second, and third place?
|
A.
|
455
|
|
B.
|
45
|
|
C.
|
2730
|
|
D.
|
3375
|
Question 5
A survey found that 85% of women in a given city enjoy shopping online. Suppose you randomly selected 6 women from the city and ask them whether or not they enjoy shopping online. Find the probability that exactly 4 say they enjoy shopping online.
Question 6
In a recent year, 11th grade New York public school students taking an English test produced test scores that were normally distributed with a mean of 81 and astandard deviation of 6. Let x be a random variable that represents a test score. What is the lowest score that would still place a student in the top 40% of the scores?
|
A.
|
79.47
|
|
B.
|
80.25
|
|
C.
|
81.48
|
|
D.
|
82.52
|
Question 7
You draw two cards from a standard deck of 52 cards without replacing the first one before drawing the second. Find the probability that the first card is an ace and that the second card is an ace?
|
A.
|
0.135
|
|
B.
|
0.004
|
|
C.
|
0.231
|
|
D.
|
0.058
|
Question 8
Find the area below the standard normal curve to the right of z = 2.
|
A.
|
0.011
|
|
B.
|
0.022
|
|
C.
|
0.978
|
|
D.
|
0.489
|
Question 9
20% of teenagers in a small town say they like reading news online. Suppose you randomly select 7 teenagers from the town and ask them whether or not they enjoy reading news online. Find the probability thatat least 3 say they enjoy reading news online.
|
A.
|
0.852
|
|
B.
|
0.966
|
|
C.
|
0.034
|
|
D.
|
0.148
|
Question 10
The lengths of Atlantic croaker fish are normally distributed, with a mean of 10 inches and a standard deviation of 2 inches. Let x be a random variable that represents the length of an Atlantic croaker fish. Suppose an Atlantic croaker fish is randomly selected. Find the probability that length of the fish is between 8.5 inches and 10.5 inches.
|
A.
|
0.63
|
|
B.
|
0.54
|
|
C.
|
0.37
|
|
D.
|
0.77
|