Question 1 2
/ 2 points
A standard normal distribution has the following
characteristics:
1) The mean
and the variance are both equal to 1
2) The mean
and the variance are both equal to 0
3) The mean
is equal to the variance
4) The mean
is equal to 0 and the variance is equal to 1
5) The mean
is equal to the standard deviation
Question 2 2
/ 2 points
The total area underneath any normal curve is equal to:
1) the mean
2) one
3) the variance
4) the
coefficient of variation
5) the
standard deviation
Question 3 2
/ 2 points
Kristen Ashford purchased the subscribers list for Wind
Surfing magazine. She plans to survey a sample of the subscribers before using
the list in her mail order business. She chooses the first 100 of the 5,000
names. Her sample is a:
1) simple
random sample
2) stratified
sample
3) systematic
sample
4) convenience
sample
5) cluster
sample
Question 4 2
/ 2 points
The area to the right of the mean in any normal distribution
is equal to:
1) the mean
2) 1
3) the
variance
4) 0.5
5) –0.5
Question 5 2
/ 2 points
If x is a normal random variable with mean 80 and standard
deviation 5, the z-score for x = 89 is:
1) 1.8
2) –1.8
3) 1.6
4) –1.6
5) 8.0
Question 6 2
/ 2 points
Within a range of z scores from –1 to +1, you can expect to
find _______ percent of the values in a normal distribution.
1) 95
2) 99
3) 68
4) 34
5) 100
Question 7 2
/ 2 points
The expected (mean) life of a particular type of light bulb
is 1,000 hours with a standard deviation of 50 hours. The life of this bulb is
normally distributed. What is the probability that a randomly selected bulb
would last more than 1100 hours?
1) 0.4772
2) 0.9772
3) 0.0228
4) 0.5228
5) 0.5513
Question 8 2
/ 2 points
Completion time (from start to finish) of a building
remodeling project is normally distributed with a mean of 200 workdays and a
standard deviation of 10 workdays. To be 99% sure that you will not be late in
completing the project, you should request a completion time of _______
workdays.
1) 211
2) 207
3) 223
4) 200
5) 250
Question 9 2
/ 2 points
Financial analyst Larry Potts needs a sample of 100
securities listed on either the New York Stock Exchange (NYSE) or the American
Stock Exchange (AMEX). According to the Wall Street Journal’s “Stock
Market Data Bank,” 2,531 NYSE securities and 746 AMEX securities were
traded on the previous business day. Larry directs his staff to randomly select
77 NYSE and 23 AMEX securities. His sample is a:
1) disproportionate
systematic sample
2) disproportionate
stratified sample
3) proportionate
stratified sample
4) proportionate
systematic sample
5) proportionate
cluster sampling
Question 10 2
/ 2 points
Suppose 40% of a student population works part time. If a
random sample size of 300 students is drawn from the population, then the
probability that 44% or fewer of the samples work part time is:
1) 0.0793
2) 0.4207
3) 0.9207
4) 0.9900
5) 1.0000
