Distributions Statistics

What is the measure of spread that is essentially the average distance from the mean of all the data.

• Standard Deviation

• IQR

• Range

• Variance

The IQR is...

• the range of the majority of the data

• the range of the middle 50% of the data around the median

• the range of the 50% of the data around the mean

• Ignorance Quotient Reaction score

The number of miles that Jenna cycled each week for a 7-week period is shown: 
36, 42, 28, 52, 48, 36, 31 
What is the median number of miles Jenna cycled?

• 24

• 36

• 39

• 52

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

• The Population

• The Sample

• The Sampling Distribution

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

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

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. 

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

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