In the Kruger and Dunning study reported in the previous two exercises, the mean estimated percentile for the 11 students in the top quartile (their actual mean percentile 5 86) was 70 with a standard...

In the Kruger and Dunning study reported in the previous two exercises, the mean estimated percentile for the 11 students in the top quartile (their actual mean percentile 5 86) was 70 with a standard deviation of 14.92, so they underestimated their abilities. Is this difference significant?