6. A researcher was attempting to calculate the average weight of children suffering from a certain disease. From patient

records, the mean was computed as 65 pounds and the standard deviation (SD) as 6 pounds. Further investigation reveals

that the scale was off, and that all readings are 2 pounds too large. For example, a patient whose weight is really 70 pounds

was weighed as 72 pounds. Therefore, the correct mean and standard deviation are:

a) mean = 65 lbs, SD = 6 lbs

b) mean = 65 lbs, SD = 4 lbs

c) mean = 63 lbs, SD = 6 lbs

d) mean = 63 lbs, SD = 4 lbs

e) It's impossible to tell without the original dataset..

7.

The payoff (X) for a lottery game has the following probability distribution. What is the expected value of payoff, X?

X, payoff: -$5 , $0 , $10

Probability: 0.60, .30 , .1

a) -$2.00

b) $2.00

c) $5.00

d) $7.00

e) none of the above

8. For which of the following would it be preferable to have a negative z-score:

a) your overall course grade (in percentage)

b) the amount of time it takes you to commute to school

c) your monthly salary

d) none of the above

9. Let X represent a random variable whose distribution is normal, with a mean of 58 and a standard deviation of 7. Which of

the following is (are) equivalent to (>65)?

I.(<51)

II. 1(<65)

III. (65)

a) I only

b) II only

c) III only

d) II and III only

e) I, II, and III

10. A poll conducted by a newspaper reported that 56% of those surveyed own an iPhone. The number 56% is a _____________.

a) population

b) parameter

c) statistic

d) sample

e) None of the above

11. Chris is enrolled in a college algebra course and earned a score of 260 on a math placement test that was given on the first

day of class. The instructor looked at two distributions of scores - one is the distribution for all first year college students who

took the test, and the other is a distribution for students enrolled in this algebra class. Both are approximately normal and

have the same mean, but the distribution for the algebra class has a smaller standard deviation. A z-score is calculated for

Chris' test score in both distributions (all first-year college students and all algebra class students). Given that Chris's score is

well above the mean, which of the following would be true about these two z-scores?

a) The z-score based on the distribution for the algebra students would be higher.

b) The z-score based on the distribution for all first-year college students would be higher.

c) The two z-scores would be the same.

d) There's not enough information to answer this question