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Sta 208: Statistical Thinking: Lab Activity 9

MM Good!

M&M candies (Mars, Inc.) are produced in six colors: blue, brown, green, orange, red, and yellow.

What is your favorite color? Is this the most frequent color?

Let’s say that you like both brown and yellow the most. In your opinion, what percentage of the M&Ms are brown or yellow?

Part II: Empirical evidence

Now let’s see what the percentage of each color appears in a sample of M&Ms.

Gently shake your bag of M&Ms so to stir up the contents.

Open your bag of M&Ms in one corner (don’t eat the sampling units, at least, not yet!).

Extract 25 candies.

Tally your results in the graph and table below. Your instructor will demonstrate.

Extract another 25 candies and tally your results.

Count the remaining candies, add the count to 50, and record the total in the table.

 

M&Ms	Number of Brown or Yellow	Percent of Brown or Yellow
First 25
Second 25
(Total) 50
How many M&Ms were in the bag?

Using the first 25 M&Ms you sampled:

What is the estimated proportion of brown or yellow M&Ms?

What is the estimated standard deviation of this proportion (among samples of size 25)?

Find the lower and upper values of a 95% confidence interval for the proportion of M&Ms in the population (from which your bag is a sample) that are either brown or yellow.

Using all 50 M&Ms you sampled:

What is the estimated proportion of brown or yellow M&Ms?

What is the estimated standard deviation of this proportion (among samples of size 50)?

Find the lower and upper values of a 95% confidence interval for the proportion of M&Ms in the population (from which your bag is a sample) that are either brown or yellow.

As a class…Discuss the results.

How many M&Ms were in your bag? Does this number vary from bag to bag? Jot down the stem plot for the M&M count among all bags opened during this lab. How would you construct a confidence interval of the mean M&M count for all bags of this size?