Estimating time needed to complete a task. In project management, estimating the length of time it takes to perform a certain task in a series of short segments generally leads to an underestimation of the total time. This theory was tested in a study published in Applied Cognitive Psychology (Vol. 25, 2011). Each in a sample of 10 subjects was asked to visualize walking a familiar route for about 20 minutes. Subjects were then asked to provide an estimate of the distance walked in several shorter time segments (e.g., in 45-second intervals) until the destination was reached. The total walking time was then determined by adding up the time segments required to reach the destination. All subjects estimated total walking time (in minutes) under each of four timesegment conditions: 45-second intervals, 2-minute intervals, 3-minute intervals, and 5-minute intervals. The data (simulated from information provided in the article) are listed in the table below. The researchers want to know if the distribution of walking times differs for the four time segments. Subject 45 Sec. 2 Min. 3 Min. 5 Min. 1 13.0 10.5 17.2 16.0 2 10.6 14.0 18.0 16.5 3 7.5 6.0 17.0 15.0 4 10.0 12.7 10.2 12.0 5 10.5 7.5 13.5 14.5 6 7.4 15.0 10.0 15.0 7 11.0 10.6 17.5 16.0 8 7.0 15.1 13.0 12.8 9 11.0 14.7 17.5 19.0 10 12.0 16.4 21.5 20.0 Source: Adapted from Applied Cognitive Psychology, Vol. 25, 2011.

a. Explain why the data should be analyzed using Friedman’s test.

b. A Minitab printout of the analysis is shown below. Locate the test statistic and p-value on the printout.

c. Using a = .01, what conclusion can you draw from the test?