Here's a familiar histogram of each person's reaction times (in distance), along with everyone combined together (heading "All").

Overall, the whole class (heading "All") appears approximately normally distributed, though somewhat right-skewed. Why might we expect this distribution to be right (upwards) skewed?

With this 3-column layout, it is difficult to compare individual performances. We could use one column and 15 rows, but that would make a very long figure. The following figure condenses each person's data, easing comparisons. This is called a box-and-whisker plot, or boxplot. The black dot shows the median, and the box shows the interquartile range (which measures the variability, similar to standard deviation). The individual points are considered outliers. For more information, see the boxplot wikipedia page.

From this, I can easily see some people's responses vary quite a bit, while others are much more consistent. I also notice that 2 people appear faster (lower distance) than the average, and one person appears slower. How might we test if these are significantly different from the rest of the class?

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