Understanding Mean and Outliers

This tutorial covers the concept of mean, a type of average, and how to calculate it using data sets. It includes examples with text messages and rainfall data, and discusses the impact of outliers on mean calculations. Practice problems are provided to reinforce learning.

What is the mean of a data set?

• The most frequently occurring value

• The middle value when the data is ordered

• The sum of the data values divided by the number of values

• The largest value in the data set

How do you calculate the mean number of text messages sent by a group of friends?

• Add all the messages and divide by the number of friends

• Multiply the number of friends by the total messages

• Find the friend who sent the most messages

• Subtract the smallest number of messages from the largest

In the rainfall example, which city had a higher average monthly rainfall?

• The city with the darker green bar

• Both cities had the same average

• City Two

• City One

What is an outlier in a data set?

• A value that is repeated most often

• The average of all values

• A value that is much greater or much less than the others

• The sum of all values

How does an outlier affect the mean of a data set?

• It always decreases the mean

• It has no effect on the mean

• It can significantly increase or decrease the mean

• It always increases the mean

In the example of Shetland ponies, what was identified as the outlier?

• A height of 45 inches

• A height of 35 inches

• A height of 40 inches

• A height of 28 inches

What was the effect of removing the outlier in the Shetland ponies' height example?

• The mean decreased

• The mean became zero

• The mean remained the same

• The mean increased

In the example of dog weights, what was the outlier?

• A weight of 25 pounds

• A weight of 15 pounds

• A weight of 20 pounds

• A weight of 8 pounds

How does the outlier affect the mean in the dog weight example?

• It has no effect on the mean

• It makes the mean equal to the outlier

• It makes the mean less than all but two weights

• It makes the mean greater than all weights

In the price example, what was the outlier?

• A price of 100

• A price of 900

• A price of 500

• A price of 300