AP Statistics Chapter 7 Sampling Distributions

The Gallup Poll asked a random sample of 1785 adults whether they attended church during the past week.  Let p-hat be the proportion of people in the sample who attended church.  A newspaper report claims that 40% of all U.S. adults went to church last week.  Suppose this claim is true. 
What is the mean of the sampling distribution of p-hat?

• 0.4
• 0.44
• 0.56
• 0.6

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What happens to the shape of a sampling distribution of sample means as n increases?

• It becomes narrower and bimodal.
• It becomes narrower and more normal.
• It becomes wider and skewed right. 
• It becomes wider and more normal. 

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These symbols represent the mean and standard deviation for which of the following distributions?

• The Population
• The Sample
• The Sampling Distribution

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The mean and standard deviation of a population are 200 and 20, respectively. Sample size is 25. 
What is the standard deviation of the sampling distribution?

• 200
• 16
• 25
• 4

At a particular college, 78% of all students are receiving some kind of financial aid.The school newspaper selects a random sample of 100 students and 72% of the respondents say they are receiving some sort of financial aid. Which of the following is true?

•  78% is a population and 72% is a sample.
• 72% is a population and 78% is a sample
• 78% is a parameter and 72% is a statistic
• 72% is a parameter and 78% is a statistic

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The average cost for a gallon of gasoline is $2.51 (source AAA.org) with a standard deviation of $0.42. Find the mean and standard error of the sampling distribution if n is decreased to 25.

• μ_x-bar = 2.51, σ_x-bar = 0.06
• μ_x-bar = 2.51, σ_x-bar = 0.084
• μ_x-bar = 0.52, σ_x-bar = 0.084
• μ_x-bar = 2.51, σ_x-bar = 0.42

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The mean weight of potato chip bags is 10.5 ounces with a standard deviation of 3 ounces. A random sample of 40 bags of potato chips is selected. What is the probability that the mean of the sample is less than 10 ounces?

• P = -1.05
• P = .1469
• P = .0202
• P = .8531

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The mean distance an OHS student travels to school is 5.6 miles with a standard deviation of 1.7 miles. Mrs. McLemore finds the mean of her 4th period class - a randomly selected sample of 29 students. What is the probability that the mean of her class is more than 6 miles?

• P = 0.00
• P = 0.1020
• P = 0.8980
• P = 1.27

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If you are to find P (x̄ ≥ 10) that means

• the probability that the sample mean is less than 10
• the probability that the sample mean is no more than 10
• the probability that the sample mean is at least 10
• the probability that the sample mean is more than 10

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According to the Center for Disease Control, 93% of children entering kindergarten in the U.S. are vaccinated. A school district has 180 incoming kindergarten children.

Which of the following is true concerning the shape of the sampling distribution?

• The sampling distribution is normal because n > 30

• The sampling distribution is not normal because nq is < 30

• The sampling distribution is normal because 10% of 180 is > 10

• The sampling distribution is normal because np and nq are both > 10

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