LESSON 2 Another Average Activity

Every week the students in Room 204 take a spelling test of 10 words. Each student records the number of words he or she spells correctly in a table. Mrs. Dewey reports the average score to the parents.

Here are Ming's scores:

Do you agree that 7 words correct is Ming's median score?
How do you find the median of a set of numbers?
Ming thinks that the 9 and the 10 should bring up his median score. Do you agree with Ming? Why or why not?

In Unit 1, you learned that an average is one number that represents a set of data. For this data, the median number of words correct is 7. Is 7 a good number to represent all of Ming's scores? Why or why not?
Averages can also be used to make predictions. Do you think 7 words correct is a good prediction for the typical score on Ming's next five spelling tests? Why or why not?

The median is a useful average because it is often easy to find. Since it is the number that is exactly in the middle of the data, it can be used to describe what is normal or typical for that data. However, we can also use another kind of average called the mean.