Stat 250 Fall 1998 Name ________________________________
Activity #3: Probability & statistical inference Student ID __ __ __ - __ __ - __ __ __ __
Section #    1      2
 
You will be given 15 minutes to complete this activity.
Form a group of 4-5 students.

Each group will be given a brown lunch bag.  Do not look in the bag throughout this activity!!

Each bag contains two kinds of mint candy.  In each bag, some of the mints are blue, and some are green.  I claim that 60% of the mints in each bag are green.  Your goal is to determine whether this is a valid claim.

To test my claim, your group will take a random sample of 30 mints from the bag (population).  To take the sample, each group should draw a mint from the bag without looking in the bag, identify and record its color, return the mint to the bag, and shake the bag before the next mint is drawn.  Repeat this sampling procedure until your group has drawn 30 mints in total.  Tally your group's results below:
 

Green Mints Blue Mints Total # of Mints Sampled
 
 
   

Once you have completed taking your random sample, answer the following questions.

What percentage of the mints sampled were green?
 
 

What percentage of the mints sampled were blue?
 
 

Based on your random sample of mints, do you think that my original claim that 60% of the mints in each bag are green is valid?  Explain your reasoning.