Suggested answer to exercise: VAS stress from the 2005 questionnaire, 5

Question 5: Where are the mode, the lower tail and the upper tail of this distribution?

Suggested answer

The median is the value which divides the distribution into two equal parts. The middle of the distribution looks to be in the interval 60 to 70 mm, about 63 mm. In fact, the median is 66 mm. It is difficult to judge accurately from the histogram and any answers within 4 mm of the correct one are good.

The first quartile, which cuts off the bottom quarter of the observations, appears to be about 43 mm. The third quartile, which cuts off the top quarter of the observations, appears to be around 79 mm. In fact, the first quartile is 48 mm and the third quartile 81 mm. Again, it is difficult to judge accurately from the histogram and any answers within 4 mm of the correct one are good. My estimate of the first quartile was not very close.

This is how they look on the histogram:

See detailed description at d. d


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