# MATHEMATICS

11.A fair die is rolled. If it comes up 1 or 2 you win $2. If it comes up 3, 4, 5, or 6 you lose $1. Find the expected winnings.

$1.00

$0.50

$0.00

$0.25

12.Assume that X is normally distributed with a mean μ = $64. Given that P(X ≥ $75) = 0.2981, we can calculate that the standard deviation of X is approximately:

$13.17.

$5.83.

$7.05.

$20.76.

13.If the attendance at a baseball game is to be predicted by the equation Attendance = 16,500 – 75 Temperature, what would be the predicted attendance if Temperature is 90 degrees?

9,750

6,750

10, 020

12,250

[The following information applies to the questions displayed below.]

A random sample of 140 items is drawn from a population whose standard deviation is known to be σ = 50. The sample mean is x = 780.

14.

(a)

Construct an interval estimate for μ with 98 percent confidence. (Round your answers to 4 decimal places.)

The 98 percent confidence interval is from to .

15.

(b)

Construct an interval estimate for μ with 98 percent confidence, assuming that σ = 100. (Round your answers to 4 decimal places.)

The 98 percent confidence interval is from to .

16.

(c)

Construct an interval estimate for μ with 98 percent confidence, assuming that σ = 200. (Round your answers to 4 decimal places.)

The 98 percent confidence interval is from to .

17.

(d) Describe how the confidence interval changes as σ increases.

The interval stays the same as σ increases.

The interval gets wider as σ increases.

The interval gets narrower as σ increases.

The interval gets wider as σ decreases.

18.What are the mean and standard deviation for the standard normal distribution?

μ = 0, σ = 1

μ = 0, σ = 0

μ = 1, σ = 0

μ = 1, σ = 1

19.A negative value for the correlation coefficient (r) implies a negative value for the slope (b1).

True

False

20.The Poisson distribution has only one parameter.

True

False

21.Find the probability that either event A or B occurs if the chance of A occurring is .5, the chance of B occurring is .3, and events A and B are independent.

.15

.80

.65

.85

22.The total sum of squares (SST) will never exceed the regression sum of squares (SSR).

True

False

23.A prediction interval for Y is narrower than the corresponding confidence interval for the mean of Y.

True

False

24.A biometric security device using fingerprints erroneously refuses to admit 2 in 1,400 authorized persons from a facility containing classified information. The device will erroneously admit 2 in 1,004,000 unauthorized persons. Assume that 95 percent of those who seek access are authorized.

If the alarm goes off and a person is refused admission, what is the probability that the person was really authorized? (Round your answer to 5 decimal places.)

Probability