Question 1: From the histogram, would you estimate the mean stress to be greater of less than the median? The median is 66 mm. What would you estimate the mean stress to be?
The distribution is negatively skew or skew to the left. The negative skewness would lead us to expect the mean to be less than the median. It is difficult to judge accurately from the histogram but I estimated the mean to be 64 mm. If we made a physical model of the bars, the mean is the point at which the model would balance on a point.
In fact, the mean is 64.8 mm. Any answers within 4 mm of the correct one are good.
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Last updated: 13 October, 2006.