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Question1)The average battery life of the iPhone 4S is reported to be 6

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Question1)The average battery life of the iPhone 4S is reported to be 6.0 hours. Assume that the standard deviation for the battery life for this cell phone is 30 minutes. A random sample of 42 iPhones had an average battery life of 5.86 hours. Which of the following statements is correct?

 

Question 2

Assume that the number of customers who arrive at a water ice stand follows the Poisson distribution with an average rate of 6.4 per 30 minutes. What is the probability that exactly two customers will arrive during the next 15 minutes?

 

Question 3

The presence of sampling error is an indication that an improper sampling technique was used.

 

Question 4

The table below shows the numbers of two- to five-bedroom houses in the Belmont neighborhood.

What is the probability that a randomly selected house will have 4 or fewer bedrooms?

 

Question 5

Your best friend proposes a bet on the basketball court. You get to attempt one free throw. If you make the free throw, your friend will pay you $20. If you miss the free throw, you will pay him $30. Based on your past performance on the court, you estimate the probability that you will make the free throw to be 59%. As a student of Statistics, you know that you should not take the bet because the Expected Monetary Value (EMV) is negative.

 

Question 6

Increasing the sample size will reduce the margin of error for a given confidence level.

 

Question 7

Bob's golf score at his local course follows the normal distribution with a mean of 92.1 and a standard deviation of 3.8. What is the probability that the score on his next round of golf will be between 82 and 89?

 

Question 8

The z-score follows a normal distribution with μ = 1 and σ = 0, which is known as the standard normal distribution.

 

Question 9

According to the Insurance Research Council, 14% of U.S. drivers are uninsured. A random sample of seven drivers was selected. What is the probability that less than three of these drivers are uninsured?

 

Question 10

DLP TVs require a special light bulb to project the picture. Assume that the average life of a DLP bulb is 1,100 hours and that this failure time follows the exponential distribution. What is the probability that a randomly selected bulb will last more than 1,500 hours?

 

Question 11

A statistics class has 140 students of which 55% are female. A random sample of 40 students was selected. What is the probability that 24 or more from this sample will be female? Hint: Consider the relationship between the sample size and the population

 

Question 12

The confidence interval for the mean is symmetrical around the population mean.

 

Question 13

The mean and standard deviation for discrete probability distributions are useful when comparing two different distributions.

 

Question 14

Increasing the sample size when calculating a confidence interval while keeping the confidence level constant will

 

Question 15

A survey by American Express Spending reported that the average amount spent on a wedding gift for a close family member is $166. A random sample of 45 people who purchased wedding gifts for a close family member spent an average of $160.50. Assume that the population standard deviation is $38. Use a 95% confidence interval to test the validity of this report and choose the one statement that is correct.

 

Question 16

The Beer Institute reported that monthly consumption of beer in 2010 was 1.7 gallons per person. A random sample of 36 adults was selected. Using a standard deviation of 0.5 gallons per month per person, what is the probability that the sample mean was between 1.6 and 1.8 gallons per month per person?

 

Question 17

The Wall Street Journal reported that the average amount of time that a French person spends eating lunch at a restaurant is 22 minutes. A hypothesis test needs to be performed to determine if a difference exists between the average time an American spends eating lunch when compared to a person from France. The following data represents the time, in minutes, that random French and American diners spent at lunch. Assume that the population variances are equal.

American	21	17	17	20	25	16	20	16
French	24	18	20	28	18	29	17

Using α = 0.10, the critical value for this hypothesis test would be ________.

 

Question 18

AutoTrader.com would like to estimate the number of years owners keep the cars that they purchased as a new vehicle. The following data shows the age of seven vehicles that were sold for the first time by their owners.

9

3

5

1

8

5

3

Using this sample, the 98% confidence interval that estimates the average age of cars sold for the first time is ________.

 

Question 19

If the purpose of the hypothesis test is to establish that a population parameter is equal to or not equal to a specific value, the

 

Question 20

Assume that the amount of time that it takes an employee to service a car at an oil change facility follows the uniform probability distribution between 21 and 38 minutes. What is the probability that a randomly selected car will require more than 30 minutes to service?

 

Question 21

When the confidence interval for the difference between two means does not include zero when testing H₀: μ₁ - μ₂ = 0, we have support that a significant difference between population means does exist.

 

Question 22

For a sample size of two or more, the standard error of the mean must be

( Assume normal distribution)

 

Question 23

The Canadian government would like to test the hypothesis that the average hourly wage for men is more than $2.00 higher than the average hourly wage for women. The following data summarizes the sample statistics for hourly wages for men and women. Assume that the population variances are equal.

If Population 1 is defined as men and Population 2 is defined as women, the correct hypothesis statement for this hypothesis test would be

 

Question 24

The National Association of Realtors reported that 26% of home buyers in the state of Florida are foreigners in 2012. The correct hypothesis statement to test the validity of this report would be

 

Question 25

The Department of Transportation would like to test the hypothesis that the average age of cars on the road is less than 10 years. A random sample of 50 cars had an average age of 9.5 years. It is believed that the population standard deviation for the age of cars is 2.4 years. The Department of Transportation would like to set α = 0.10. The p-value for this hypothesis test would be ________.

 

Question 26

Breyers is a major producer of ice cream and would like to test the hypothesis that the average American consumes more than 17 ounces of ice cream per month. A random sample of 15 Americans was found to consume an average of 18.2 ounces of ice cream last month. The standard deviation for this sample was 3.9 ounces. Breyers would like to set α = 0.10.

Which one of the following statements is true?

 

Question 27

Which of the following statements is true regarding the normal probability distribution?

 

Question 28

Sony would like to test the hypothesis that the average age of a PlayStation user is different from the average age of an Xbox user. A random sample of 32 PlayStation users had an average age of 33.7 years while a random sample of 36 Xbox users had an average age of 35.6 years. Assume that the population standard deviation for the age of PlayStation and Xbox users is 3.7 and 3.5 years, respectively. Sony would like to set α = 0.05. The critical value for this hypothesis test would be ________.

 

Question 29

The Canadian government would like to test the hypothesis that the average hourly wage for men is more than $2.00 higher than the average hourly wage for women. The following data summarizes the sample statistics for hourly wages for men and women. Assume that the population variances are equal.

If Population 1 is defined as men and Population 2 is defined as women, and using α = 0.025, which one of the following statements is true?

 

Question 30

A golfer claims that his average golf score at the course he plays regularly is less than 90. The correct hypothesis statement for this golfer to prove his claim would be