QUESTION 1

Please use the NDT table to answer the following question:

Readings on a thermometer are normally distributed with a mean of 0C and a standard deviation of 1.00.

What is the probability that a randomly selected thermometer reads:

a. Less than -0.67.

b. Greater than -1.34

c. Between -1.56 and 2.07

d. Greater than 0.98

e. Less than -2.65 or greater than 2.65

Choose one 10 points

The probabilities are:

a. 0.2514

b. 0.0901

c. 0.9808

d. 0.1635

e. 0.0040

The probabilities are:

a. 0.2514

b. 0.9099

c. 0.9214

d. 0.1635

e. 0.0080

The probabilities are:

a. 0.2514

b. 0.0901

c. 0.9808

d. 0.1635

e. 0.0080

The probabilities are:

a. 0.2514

b. 0.9099

c. 0.9214

d. 0.1635

e. 0.0040

QUESTION 2

In a survey, 498 out of 1,397 US adults said they drink at least 4 cups of coffee a day. Find a point estimate (P) for the population proportion of US adults who drink at least 4 cups of coffee a day, then construct a 90% confidence interval for the proportion of adults who drink at least 4 cups of coffee a day.

Choose one 10 points

P=0.3565; (0.4454, 0.3776)

P=0.3565; (0.3354, 0.3336)

P=0.3475; (0.3354, 0.3776)

P=0.3565; (0.3354, 0.3776)

QUESTION 3

Your firm wants to investigate how much money the typical tourist will spend on their next visit to New York. How many tourists should be included in your sample if you want to be 95% confident that the sample mean is within $18 from the population mean? From previous studies, we know that the standard deviation is $62.

Choose one 10 points

45

46

47

48

QUESTION 4

A study of women's weights found that a randomly selected sample of 300 women had a mean weight of 150 lb. Assuming that the population standard deviation is 18.2 lb., construct a 95% confidence interval estimate of the mean weight of all women. Choose the correct interval from below:

Choose one 10 points

(147.294, 152.706)

(147.940, 152.060)

(147.904, 152.060)

(147.915, 152.085)

QUESTION 5

Assume that adults have IQ scores that are normally distributed, with a mean of 105 and a standard deviation of 17. Find the probability that a randomly selected individual has an IQ between 70 and 115. Choose the correct value:

Choose one 10 points

0.7024

0.7027

0.7029

0.7031

QUESTION 6

Construct a confidence interval for the population mean using a t-distribution:

c = 95% m = 18 s = 5 n = 25. Choose from the intervals listed below.

Choose one 10 points

(15.940, 20.060)

(15.963, 20.604)

(15.904, 20.006)

(15.936, 20.064)

QUESTION 7

A music industry researcher wants to estimate, with a 90% confidence level, the proportion of young urban people (ages 21 to 35 years) who go to at least 3 concerts a year. Previous studies show that 21% of those people (21 to 35 year olds) interviewed go to at least 3 concerts a year. The researcher wants to be accurate within 1% of the true proportion. Find the minimum sample size necessary.

Choose one 10 points

4142

663

945

4489

QUESTION 8

Find the critical value of t for a sample size of 27 and a 99% confidence level. Choose the correct value from below:

Choose one 10 points

2.771

2.779

2.717

2.797

QUESTION 9

Men's heights are normally distributed with a mean of 72 inches and a standard deviation of 3.1 inches. A social organization for short people has a requirement that men must be at most 66 inches tall. What percentages of men meet this requirement? Choose the correct answer:

Choose one 10 points

2.62%

2.59%

2.56%

2.68%

QUESTION 10

The mean rent of a 3-bedroom apartment in Orlando is $1200. You randomly select 12 apartments around town. The rents are normally distributed with a standard deviation of $300. What is the probability that the mean rent is more than $1100?

Choose one 10 points

0.1827

0.8173

0.1251

0.8749