Chapter 6 and 7

Binomial

100

The National Coffee Association reports that among individuals in the 16-21 age bracket 52% drink coffee. Nine people in this age bracket are selected. What is the mean of the number of people in this age bracket that drink coffee?

4.68

200

The National Coffee Association reports that among individuals in the 16-21 age bracket 52% drink coffee. Nine people in this age bracket are selected. What is the standard deviation of the number of people in this age bracket that drink coffee?

1.5

300

The National Coffee Association reports that among individuals in the 16-21 age bracket 52% drink coffee. Nine people in this age bracket are selected. Find the probability that exactly four of them drink coffee.

0.2347

400

The National Coffee Association reports that among individuals in the 16-21 age bracket 52% drink coffee. Nine people in this age bracket are selected. Find the probability that less than three of them drink coffee. 

0.7839

500

60% of Americans 20 and older drive to work. If 10 people in this age bracket are selected, find the probability that exactly 2 of the 10 drive to work.

0.0106

Normal

100

Suppose the amount of time an adult spends using Facebook per month follows a normal distribution with a mean of 7.4 hours and standard deviation 0.65 hours. What is the probability that a randomly selected adult spends less than 6.2 hours per month using Facebook?

0.0322

200

A survey of U.S. adults found that 76% would pay more for an environmentally friendly product. A random sample of 175 adults is selected. What is the probability that more than 125 say they would pay more for an environmentally friendly product?

0.9222

300

Suppose it is known that 32% of adults have hypertension. If 175 adults are selected at random, what is the probability that less than 34% have hypertension?

0.7157

400

A certain medical procedure produces side effects in 25% of the patients who receive it. A random sample of 130 adults who receive this procedure is selected. What is the probability that more than 44 of the sample of 130 patients have side effects from the procedure?

0.0099

500

The response time calls for calls to the New York fire department is normally distributed with mean of 5 and standard deviation 1.5 minutes. What is the probability the response time for a call is between 3.8 and 6 minutes?

0.5367

Inverse Normal

100

Yearling Angus steers have weights that follow a normal model with mean weight 1152 pounds and standard deviation 84 pounds. What percent of steers weigh less than 1200 pounds?

71.57%

200

 The 9% of MD-80 jet airliners that are the least expensive to operate cost no more than what amount per hour to operate?

$1852.50

300

The weight of US male babies less than two months old is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. 10% of babies less than two months old weigh more than what amount? 

14.957

400

Scores on a math assessment test are normally distributed with a standard deviation of 15. If only 7.5% of the scores are above 300, what is the mean of the distribution?

278.4

500

The invnorm function gives the area to the right. TRUE or FALSE?

FALSE

Empirical Rule

100

The scores on a nationally administered test are normally distributed with a mean of 63 and standard deviation 8. Use the Empirical Rule to answer the following questions. 1. What percentage of students scored between 47 & 87?

97.35%

200

The scores on a nationally administered test are normally distributed with a mean of 63 and standard deviation 8. Use the Empirical Rule to answer the following questions. 1. What must a student score to be at the 97.5th percentile for this test?

79

300

A job satisfaction assessment is standardized to a normal model with the mean 100 and standard deviation 12. According to the Empirical Rule what percentage of people would have job satisfaction scores between 64 and 112? 

83.85%

400

A normal model has a standard deviation of 6 and a mean of 31. What percentage of the data is between 19 and 37?

81.5%

500

A normal model has a standard deviation of 51 and a mean of 108. What percentage of the data is between 108 and 210?

37.5%

Random

100

The amount of candy a person eats at Halloween is normally distributed with a standard deviation of 2 ounces. What is the average amount of chocolate eaten (in ounces) if only 4% of people eat more than 7 ounces of candy at Halloween?

3.5

200

A consumer organization inspecting new cars found that 61% had no defects, 21% had one defect, 11% had two defects and 7% had three defects. What is the expected number of defects in a new car?

0.64

300

Suppose Susan scored a 700 on the SAT test and that placed her on the 84th percentile. The SAT test is normally distributed with standard deviation 45. What was the mean score?

655

400

Suppose 98% of Americans celebrate a particular holiday with family. A random sample of 300 Americans is selected. Can we use the normal approximation to estimate the probability that exactly two celebrate this holiday with family?

NO: n(1-p) is too small

500

When using the normal distribution to approximate a binomial the sample size should be more than 10% of the population. TRUE or FALSE?

FALSE