ISI
Lab 9

1: Introduction 2: Research Question 1 3: Inference 4: Research Question 2 5: Inference 6: Research Question 3 7: Inference 6: Research Question 4 7: Inference 8: Research Question 5 9: Research Question 6
Labs

Research Question 1: Do students at Cal Poly tend to carry more than the recommended weight?

Because the recommendation is in terms of "percentage of body weight," we first need to compute the backpack to body weight ratios. Do this in the Excel file (e.g, in Column C, use =a2/b2 and then double click on the lower right corner to fill down the column).

Now copy and paste all of the columns into your software of choice.

Descriptive Statistics

(a) Produce a graph to display the distribution of backpack to body weight ratios.

Press one of the links below to view the appropriate technology instructions.

JMP

Minitab

R

Applets

Choose Analyze > Distribution Drag the ratio variable from the Select Columns box next to the Y, columns button. Press OK The output will include relevant numerical summaries as well.

Choose Stat > Basic Statistics > Display Descriptive Statistics Double click on the ratio variable in the left window to place it in the Variables box. Press the Graphs and check the Histogram of data, with normal curve option. Press OK twice.

hist(backpackdata$ratio, xlab="ratios") summary(backpackdata$ratio) sd(backpackdata$ratio)

Open the Descriptive Statistics applet and paste in only the ratio data from Excel (with the header). Press Use Data Use the radio button to change to a Histogram. Check the boxes to display the Actual Mean and Std dev.

Remember to do any formatting (e.g., fix the axis label) and then take a screen capture of the relevant output and paste into your lab report.

(b) Summarize what you learn.