Business Statistics Chapter 7 Quiz

Which of the following is true regarding the normal distribution? A. the mean, median, and mode are all equal B. it has two modes C. it is asymmetrical D. the points of the curve meet the x-axis at z=-3 and z=3

A. the mean, median, and mode are all equal

A group of normal distributions can have equal arithmetic means but different standard deviations A. true B. false

A. true

When referring to the normal probability distribution, there is not just one; there is a "family" of normal probability distributions A. true B. false

A. true

Within plus and minus one standard deviation of the mean, the area under and normal curve is about 68% A. true B. false

A. true

The total area of normal probability distribution is _____. A. between -3.0 and 3.0 B. 1.00 C. dependent of the value of "z" D. approximated by the binomial distribution

B. 1.00

Some normal probability distributions are positively skewed A. true B. false

B. false

Which of the following is a characteristic of the normal probability distribution? A. its positively skewed B. its bell shaped C. its asymmetrical D. its rectangular

B. its bell shaped

What is an important similarity between the uniform and normal probability distribution? A. the mean, median, and mode are all equal B. the mean and median are equal C. they are negatively skewed D. about 68& of all observations are within one standard deviation

B. the mean and median are all equal

for the normal distribution, the mean plus and minus two standard deviations will include about what percent of the observations? A. 50 % B. 99.7% C. 95% D. 68%

C. 95%

The shape of any uniform probability distribution is _____. A. negatively skewed B. positively skewed C. rectangular D. bell-shaped

C. rectangular

Two normal distributions are compared. one has a mean of 10 and a standard deviation of 10. the second normal distribution has a mean of 10 and a standard deviation of 2. which of the following is true? A. the locations of the distributions are different B. the distributions are from two different families of distributions C. the dispersions of the distributions are different D. the dispersions of the distributions are the same

C. the dispersions of the distributions are different

Which of the following is true in a normal distribution? A. the mean equals zero B. the mode and the third quartile are equal C. the mean divides the distribution into two equal areas D. the area under the curve is .68

C. the mean divides the distribution into two equal areas

Tables of normal distribution probabilities are found in many statistics books. These probabilities are calculated from a normal distribution with _____. A. a mean of 1 and a standard deviation of 1 B. a mean of 100 and a standard deviation of 15 C. a mean of 0 and a standard deviation of 15 D. a mean of 0 and a standard deviation of 1

D. a mean of 0 and a standard deviation of 1