Research Question 2: Do students who report back problems tend to carry more weight (higher ratios)?
(d) Is whether or not students report back problems a quantitative or a categorical variable?
Descriptive Statistics
(e) Use an technology to produce numerical and graphical summaries comparing the backpack to body weight ratios for those with and without back problems.
 Choose Analyze > Fit Y by X
 Move ratio into the Y, Response box and >Back problems into the X, Factor box.
 Press OK
 Use the hot spot to select Display Options > Box Plots.
 Use the hot spot again to select Means and Std Dev
.


 Choose Stat > Basic Statistics > Display Descriptive Statistics
 Move the ratio variable to the Graph variables box and then click in the By variables box and enter the Backproblems variable.
 Press the Graphs button and choose Boxplot of data
 Press OK twice.


 boxplot(backpackdata$ratio~backpackdata$Backproblems, horizontal=T)

 In the Excel file, get the ratio and Backproblems columns next to each other. Make sure the Backproblems header is one word.
 Copy and paste these two columns two your clipboard

Open the Theory Based Inference applet
 Use the pulldown menu to select the Two means scenario.
 Check the Paste data, Stacked, and Includes header boxes.
 Paste in the two columns from your clipboard.
 Toggle the (Value Group) button to match the format of your data.
 Press Use Data.


Include this output in your report.
(f) Write a paragraph comparing the behavior of the ratios in these 2 groups (any similarities, any differences), remembering all previous lessons on what to talk about.