The histogram shows the distribution of mean ACT mathematics scores for all Wisconsin public schools in 2011. The vertical lines show the mean and one standard deviation above and below the mean. 78.8% of the data points are between the two outer lines.
a) Give two reasons that a Normal model is not appropriate for these data.

b) The Normal probability plot on the left shows the distribution of these scores. The plot on the right shows the same data with the Milwaukee area schools (mostly in the low mode) removed. What do these plots tell you about the shape of the distributions?

Transcribed Image Text:

12 14 6 18 20 22 24 26 28 Average Score Math 28 g 24 8 22 20 18 16 20 18 16 14+ -4-3-2-101 2 3 4 Normal Quantle -4-3-2-1 012 3 4 Normal Quantile