AP Stat Sampling

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. 

The average annual salary for 35 of a company's 1200 accountants is $68,000.

• parameter

• statistic

This distribution is ​ (a)   so we should use the ​ (b)   as a measure of center and the ​ (c)   as a measure of variability.

• fairly symmetric

• mean

• range

• left skewed

• mode

• median

• IQR

• right skewed

The founder of Walmart is interested to know the average amount of money the stores lose in returned or damaged merchandise. They randomly pick two stores in each state and calculate the amount of money each store lost. Which best describes the sampling method used

• SRS

• Stratified random sample

• Cluster sample

• Systematic Sample

The founder of Walmart is interested to know the average amount of money the stores lose in returned or damaged merchandise. They randomly pick 5 states and find the amount of money all of the stores in those states lost to returned or damaged merchandise. Which best describes the sampling method used?

• SRS

• Stratified random sample

• Cluster sample

• Systematic Sample

An auto analyst is conducting a satisfaction survey, sampling from a list of 10,000 new car buyers. The list includes 2,500 Ford buyers, 2,500 GM buyers, 2,500 Honda buyers, and 2,500 Toyota buyers. The analyst selects a sample of 400 car buyers, by randomly sampling 100 buyers of each brand.

• Random

• Stratefied

• Systematic

• Cluster

Match the following

• Voluntary Response

• Readers choose to respond to a poll

• Systematic

• Randomly select 6 stores from each of the states

• Stratified

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

• Cluster

• Survey all employees at 5 randomly selected stores

• SRS

• Select every 5th student

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