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 5: Does the average backpack-to-body ratio depend on a student's college?

Based on self-reported majors I attempted to classify everyone into one of the 6 colleges ("college").

Descriptive Statistics

(p) Use technology to construct an appropriate graphical display for examining the relationship between backpack-to-body ratio and college. Include this graph in your report.

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

JMP

Minitab

R

Applets

Select Analyze > Fit Y by X. Move ratio into the Y, Response box and >college into the X, Factor box. Use the hotspot to add boxplots to the display.

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 college variable. Press the Graphs button and choose Boxplot of data. Press OK twice.

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

In the Excel file, get the ratio and Units columns next to each other. Copy and paste these two columns two your clipboard Open the Descriptive Statistics applet Check the stacked and includes header boxes. Please Clear and then paste in the data. Toggle the (categ, quant) button to match your data format. Display the means, standard deviations, and boxplots.

(q) Write 1-2 sentences describing the relationship as revealed by your graph.

 

Inferential Statistics

(r) Carry out a test of significance to decide whether there is an association between backpack-to-bodyratio and college among all Cal Poly students.

1. Define the parameter(s) of interest.

2. State the hypotheses both in symbols and in words.

3. Identify an appropriate test procedure.

4.-5. Use technology to carry out the test of significance and copy the output into your report.

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

JMP

Minitab

R

Applets

Using your earlier output, use the hotspot to select Means/ANOVA.

Select Stat > ANOVA > One-Way. Remember to specify the Response variable and the Factor (Explanatory variable). PressOK.

summary(aov(backpackdata$ratio~backpackdata$college))

Copy and paste the data into the Multiple Means applet. Remember to specify the Response and Explantory variables before pressing Use Data. Check the Show ANOVA Table box.

6. State your decision and summarize your conclusions in context.