Menu Search Times: Estimating time to scan and select menu items

Overview

For this assignment, you will be studying the relationship between the position of a hyptertext link in a list and the time needed to click on that link.

Background

A Web navigation study asked participants to find various retail goods in a Web site. They searched for items like coffee grinders, electric mixers and chopsticks. One such item was a "birdbath". When they reached the page with this item, they had to scan a list of 11 links. The link labeled "Birdbath" was randomly positioned among the 11 links. The file menu.xls has the timing results. Each row represents one navigation result. The first column is the position in the list where the desired link ("Birdbath") was located (numbered 1 through 11, from top to bottom). The second column is the time in milliseconds needed to scan the links and click on the desired link. Assuming that people scan lists from top to bottom, a low target position should have a faster click time.

Procedure

1. Using Excel or some statistics package, create a scatter plot of the data. Have the link position be the independent variable (x-axis) and the time be the dependent variable (y-axis).
2. Report the mean and standard deviation for both variables.
3. Using Excel or the statistics package draw the regression line and report the equation of the regression line.

Analysis and questions

1. What is the slope of the regression line?
2. What is the y-intercept of the regression line?
3. What is the correlation coefficient (r)?
4. Using the equation for the regression line, predict how much time it would take an average user to scan the menu and click on the fourth item.
5. Based on the equation for the regression line, how much time does an average user require to scan each link?
6. Based on the equation for the regression line, how much time does it take for a user to click on a link (after the user has scanned and found the needed link)?
7. To what extent did these participants scan the list from top to bottom? Discuss.