Measures of Centre and Spread

What is the range?

• The sum of the largest and smallest number

• The number in the middle

• The difference between the largest and smallest number

• The number that appears most often

At Donald's Donuts the number of donuts in a bag can vary. Determine the mode.

12, 10, 10, 10, 13, 12, 11, 13, 10

The number of miles that Jenna cycled each week for a 7-week period is shown:  36, 42, 28, 52, 48, 36, 31 

Calculate the median number of miles Jenna cycled?

Consider the data set below:

2, 5, 12, 15, 142

Determine the value of the median without the outlier included?

What measure of center is best to use when we have outliers?

• mean

• median

• mode

• range

A class scored 83,83,87,87,88,88,91,94,95,96,98,100,100 on a test, but then a student scored a 28.

The mean will ​ (a)  

The median will ​ (b)  

The ​ (c)   is the best measure of center for this data.

• decrease

• increase

• stay the same

• go up

• go down

• median

• mean

Which summary statistic should be used to compare the two data sets and why?

• The median and the interquartile range because they are normally distributed.

• The median and the interquartile range because they are skewed.

• The mean and the standard deviation because they are normally distributed.

• The mean and the standard deviation because they are skewed.

Which statistic measures how spread out the data values are in a data set?

• mean

• mode

• maximum value

• standard deviation

Calculate the mean of the data set:

8.9, 9.4, 8.6, 9.1

Calculate the range of the data.

63, 71, 65, 66, 87, 53