5.

Highlight the list of numbers you require the mean for, which will appear in the number 1 box (ignore number 2 box) and click ok

Interquartile Range – This is also a measure of spread but looks at the spread of the middle 50% of the data around the median. It is found by subtracting the lower quartile from the upper quartile (calculating UQ-LQ).

To Calculate Quartiles in Excel:

##### The Lower Quartile

1.

Click in an empty cell

2.

Click on fx on the tool bar

3.

Select Statistical in the function category

4.

Select Quartile in the function name and then click ok

5.

Highlight the column of data, which will appear in the array box

6.

Click in quart box and type 1

7.

Click ok

To calculate the Minimum, repeat as above but type in 0 instead of 1 in the quart box

To calculate the Median, repeat as above but type in 2 in the quart box

To calculate the Upper Quartile, repeat as above but type in 3 in the quart box

To calculate the Maximum, repeat as above but type in 4 in the quart box

#### Drawing Box and Whisker Diagrams

1.

Use graph paper

2.

Draw a horizontal scale. It is a good idea to draw all the box plots on one piece of graph paper using the same scale. You will then be able to compare your results in your conclusion.

3.

Mark on the 5 pieces of data you have found and draw in the box and whiskers as shown on the next page.

Lower Quartile

#### Median

Upper Quartile