AP Stat Sampling Distribution

28% of all Woodrow students believe Monday will be snow day. You take a sample of 50 students and find that 15 of them believe Monday will be a snow day. What does 50 represent? 

• n

• P

• phat

• standard deviation

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. What is the mean and standard deviation of the population distribution?

The following graphs show the sampling distributions for two different point estimators, R and W, of the same population parameter. Which of the following statements is true?

• Both R and W are unbiased.

• R is biased, and W is unbiased

• Both R and W are biased.

• R is unbiased, and W is biased.

• The assessment of bias is not possible, because the sampling distributions display too much variability.

What word best describes this definition: a numerical value that is calculated from a sample. Mean or average from the sample, denoted x̄ (x-bar).

• Population

• Sample

• Parameter

• Statistic

A statistic is biased if...

• the value of the statistic from any sample is NOT equal to the parameter

• The value of the statistic from any sample IS equal to the parameter

• The mean of the sampling distribution is NOT equal to the true value of the parameter

• The mean of the sampling distribution IS equal to the value of the parameter

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. 

Describe the shape of the distribution.
 

• Skewed Left

• Skewed Right

• Symmetric

• Uniform

Which of the following best describes the shape of the distribution?

• SKEWED LEFT

• SKEWED RIGHT

• SYMMETRICAL

The founder of Walmart is interested to know the average amount of money the stores lose in the United States in returned or damaged merchandise. They randomly pick 10 stores from NC and determine the money lost. Which statement best describes the generalizations the founder can make from their data.

• Since they took a random sample, they can use their data to make a generalization about all US Walmart stores

• Since their sample only came from one state, they should not make any generalizations about all US Walmart stores

Match the following

• Systematic

• Survey all employees at 5 randomly selected stores

• Cluster

• Number the players 1 - 1000 and use a random number generator to select 50

• Stratified

• Randomly select 6 stores from each of the states

• Voluntary Response

• Readers choose to respond to a poll

• SRS

• Select every 5th student