3. Results

More detailed statistical results for the t-tests and ANOVAs appear in A.5.

Task Completion Time

The graph and table below show the results for the mean time to complete a given task in seconds.Two sample t-tests assuming unequal variances were run for every combination of browser type withineach instance of # of thumbnails. The tests showed that only the results for the 5x5 grid of thumbnailswere statistically significant for an alpha of 0.05. Additionally, 3x1 single-factor ANOVAsshowed that only in the 5x5 treatments did the browser type have a significant effect on task time.Similar stastistics were carried out for all dependent variables.



Error Rates

As expected, the task error rates were generally very low, and most of the results were not stasticallysignificant. However, t-tests showed that for the 5x5 treatment, a statistically significant differencedid exist between the button and scrollbar interfaces for alpha=0.05.



Subjective Satisfaction

The degree of subjective satisfaction was measured on a 1 to 5 scale, where 5 corresponded with Frustratingand 1 corresponded with Satisfying. The ANOVAs showed that for both instances of # of thumbnails theinterface type did have a statistically significant effect on user satisfaction. Additionally, all t-testsshowed significant results at an alpha of 0.05 except between the scrollbar and the velocity slider using the 5x5 grid.



Subjective Difficulty

The degree of subjective difficulty was measured on a 1 to 5 scale, where 5 corresponded to Very Hardand 1 corresponded to Very Easy. The ANOVAs in this case showed that for the 3x3 treatments, interface typedid not have a statistically significant effect on the users' percieved difficulty of the task.However for the 5x5 treatments, interface type did have a significant effect. T-tests showed that betweenthe button and velocity slider interfaces for the 3x3 grid, a significant difference did exist, and for the5x5 grid statistically significant differences existed between the button and scrollbar interfaces and between the buttonand velocity slider interfaces.



Subjective Predictability

The degree of Predictability was measured on a 1 to 5 scale, where 5 corresponded to Unpredictable and 1corresponded to Predictable. The results here are almost exactly the same as that collected for SubjectiveSatisfaction, except that stastically significant differences did not exist between the scrollbar and buttoninterfaces for the 3x3 grid, and between the scrollbar and velocity slider interfaces for the 5x5 grid.