Stat 250 Fall 1998 Name ________________________________
Activity #9: Confidence intervals for mean Student ID __ __ __ - __ __ - __ __ __ __
Section #    1      2
 
Form a group of 4 students.  You will be given 10 minutes to complete this activity.

What is the length, in millimeters, of the middle finger on your dominant hand?
 

___ ___ ___ millimeters

Compile your group's data by recording the lengths of each person's middle finger:
 
 

Person 1 Person 2 Person 3 Person 4
                  
 

Calculate your sample's average:  ________
 

Calculate your sample's standard deviation:  ________
 
 

Calculate a 95% confidence interval for the average length of Stat 250 student's middle fingers:
 
 
 
 

Write one statement that summarizes the results of your interval:
 
 
 

Do you have any concern about using this interval to draw conclusions about the actual average length of Stat 250 student's middle fingers?  Explain.