# STATS

posted by
**Judy and group** on
.

12- The number of cars sold annually by used car salespeople is normally distributed with a standard deviation

of 19.22. A random sample of salespeople was taken and the number of cars each sold is listed her.

79 43 58 66 101 63 79 33

58 71 60 101 74 55 88

The 95% confidence interval estimate of the population mean is

(1) (58.873; 78.327)

(2) (66.099; 71.111)

(3) (686.000; 255.542)

(4) (68.600; 78.327)

(5) (588.730; 783.270)

ANSWER:2

13-A random sample of 40 men drank an average of 20 cups of coffee per week during examination final,

with the population standard deviation equal to 6 cups. A lower limit of an approximate 95% confidence

interval the population average cup of coffee is

(1) 20.000

(2) 21.859

(3) 19.708

(4) 18.141

(5) 19.051

ANSWER: 4

14-In a random sample of 500 students, 80% say they have a part-time job. An approximate 95% confidence

interval for the proportion of students with part-time jobs is:

(1) (0.758; 0.842)

(2) (0.765; 0.835)

(3) (0.770; 0.830)

(4) (0.800; 0.835)

(5) (0.782; 0.819)

ANSWER:4

15-Which statement is incorrect?

(1) A null hypothesis is a statement about the value of a population parameter; it is put up for testing in

the face of numerical evidence.

(2) An alternative hypothesis is an assertion that holds if the null hypothesis is false.

(3) A one-tail test is one in which a null hypothesis can be rejected by an extreme result in one direction

only.

(4) A two-tail test is one in which a null hypothesis can be rejected by an extreme result occurring in either

direction.

(5) A pâ€“value greater than 0.05 means that the null hypothesis can be rejected at the 5% significance level.

ANSWER: 5