Quartiles and Interquartile Range (IQR)

Why do we use measures of variation within a set of data?

• To make a dot plot.

• To find the mode.

• To find the mean.

• To determine how spread out the data is.

What will he need to do to find the range?

• Find the difference between the greatest value and the least value.

• Find the middle.

• Find the number that appears most often.

• Find the average.

What is the range for this set of data?

• 18

• 13

• 13.5

• 12.5

Pause the video until you find your answer. You can show your work on the back cover of your packet. Then type your answer here. 

What is the median for this set of data?

• 29

• 37

• 28

• 30

What is the median of the lower half of the numbers?

• 29

• 23

• 21.5

• 22

What is the median of the upper half of the data?

• 32

• 34

• 29

• 31.5

What is the interquartile range (IQR) for this set of data?

• 32

• 19

• 22

• 10

What are the values of the 1st quartile and 3rd quartile?

• 240 and 260

• 235 and 250

• 230 and 250

• 235 and 255

What is the interquartile range (IQR) for this set of data?

• 25

• 30

•  245

• 20