Question 1:

Describe the relationship between the height and weight of the subjects. To describe the relationship write about the pattern (direction, form, and strength) and any deviations from the pattern (outliers).

So far we have studied the relationship between height and weight for all of the males and females together. It may be interesting to examine whether the relationship between height and weight is different for males and females. To visualize the effect of the third variable, gender, we will indicate in the scatterplot which observations are males and which are females.

To open Excel with the data in the worksheet, clickhereand it will automatically download the file to your computer. Find the downloaded file (usually in the Downloads folder) and double-click it to open it in Excel.

As you can see, our dataset contains the following variables:

gender:0 = male, 1 = female.

height:in inches.

weight:in pounds.

First we will create a scatterplot to examine how weight is related to height, ignoring gender.

To do that in Excel:

• Sort the data by gender:
• Hold down theControlkey (Commandkey on MacOS) and click theAkey to select all of the data in the worksheet.
• Select theHometab, then theEditinggroupSort & Filter -> Custom Sort.
• In the pop-up window, make sure thatMy list has headersbox is checked and then choosegenderfrom the pull-down menu next toSort by. ClickOK.
• Now select all of the data in columns B and C, select theInserttab and in theChartsgroup chooseScatter.
• Choose the first scatterplot option (Scatter with only Markers).
• Now we have a scatterplot, but the data is all on the right of the plot. To fix this:
• Right-click on the x-axis, and chooseFormat Axisfrom the pop-up menu.
• Make sure thatAxis Optionsis selected on the left, and then next toMinimumenter50in the textbox. Click theXbutton to close the menu.

Question 2:

Compare and contrast the relationship between height and weight for males and females. To compare and contrast the relationships by gender write about the pattern (direction, form, and strength) and any deviations from the pattern (outliers) for each group.

Discuss how the patterns for the two groups are similar and how they are different.

To do that in Excel:

• Right-click on one of the data points in your scatterplot and chooseSelect Datafrom the pop-up menu.
• Right now only one series is shown, and it is labeledweight. This series currently includes all of the data points for both male and female. We're going to change this series to represent only males, and add a new series to represent females. To do this:
• Click on theweightseries to select it.
• In the box to the right underName, typemales.
• In the box underX values, change the formula so that the range includes only the data for males. In this case, you would change it to=Sheet1!$B$2:$B$58. Change the formula in the box underY valuesin the same manner. ClickOK.
• To add a new series click on the+button underneath the Legend entries (Series) box.
• Select theSeries2title, typefemalesin theNamebox.
• The easiest way to get the formulas right for theSeries X valuesandSeries Y valuesis to copy and paste the formulas from the male series. Do that and change the data range appropriately. In our case, for example, the formula forSeries X valuesfor thefemalesseries would be=Sheet1!$B$59:$B$82.
• Click theOKbutton when you're done.

You should now see two colors on the scatterplot, one for males and one for females, with the legend indicating which is which.