Question

A z score of 1.25 represents an observation that is

a) 1.25 standard deviation below the mean.

b) 0.25 standard deviations above the mean of 1.

c) 1.25 standard deviations above the mean.

d)         both b and c

Assume that your class took an exam last week and the mean and standard deviation of the exam were 85 and 5, respectively. Your instructor told you that 30 percent of the students had a score of 90 or above. You would probably

a) think that your instructor was out of her mind.

b) decide that your score of 80 would probably fall in the failing range.

c) conclude that the scores were not normally distributed.

d) conclude that such a set of scores could not possibly happen.

Which of the following is NOT always true of a normal distribution?

a) It is symmetric.

b) It has a mean of 0.

c) It is unimodal.

d) both a and b

If the test scores on an art history exam were normally distributed with a mean of 76 and standard deviation of 6, we would expect

a) most students scored around 70.

b) no one scored 100 on the exam.

c) almost equal numbers of students scored a 70 and an 82.

d) both a and c

The difference between a normal distribution and a standard normal distribution is

a) standard normal distributions are more symmetric.

b) normal distributions are based on fewer scores.

c) standard normal distributions always have a mean of 0 and a standard deviation of 1.

d) there is no difference.

The most common situation in statistical procedures is to assume that

a) data are positively skewed.

b) data are negatively skewed.

c) data are normally distributed.

d) it doesn't make any difference what the distribution of the data looks like.

Answer 1