Stat 250 Fall 1998 Name ________________________________
Activity #8: Sampling distributions Student ID __ __ __ - __ __ - __ __ __ __
Sheet 2 Section #    1      2
 
Using the random number table and the available data, take 4 different random samples of 4 people each.  For each random sample, calculate the sample's average and the sample's maximum.
 
 
Random
Sample #
Data Sample Average Sample Maximum
1 ____    ____    ____    ____           
2 ____    ____    ____    ____             
3 ____    ____    ____    ____             
4 ____    ____    ____    ____              
 
Tear along the dotted line, and hand in the above sheet to your instructor as soon as you complete it.
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After you have completed the above, work with at least one other student in answering the following questions:

1.  A probability distribution of a statistic, such as a sample average, is called a sampling distribution.  If we created a histogram or dotplot of all of the class' above sample averages, what do you think the shapes of the distributions would look like?
 
 
 

2.  Again, a probability distribution of a statistic, such as a sample maximum, is called a sampling distribution.  If we created a histogram or dotplot of all of the class' above sample maximums, what do you think the shapes of the distributions would look like?
 
 
 

3.  The average of all of the sample averages can be thought of as the "mother of all averages."  What do you think the average of all of the class' sample averages will equal?
 
 
 

4.  We can also calculate the standard deviation of all of the class' sample averages.  When we take the standard deviation of sample averages, we call it standard error rather then standard deviation.  Suppose the standard error is 3.25 for sample averages based on samples of 4 people.  Do you think the standard error would increase, decrease, or stay the same if we instead took samples of, say, 16 people?