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Intro-Stat, Math 203, Candy bar Quiz 1
  1. The length, in inches, of trout in a blue ribbon stream are distributed in an approximately normal manner with a mean of 15 inches and a standard deviation of 2.7 inches.
    1. What proportion of trout in this stream exceed 21 inches in length?

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    2. New regulations require that all trout from 12 to 16 inches are released (if caught). What proportion of trout in this stream have lengths from 12 to 16 inches?

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    3. How long would a trout have to be if it was amongst the longest 5% of all trout in the stream?

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  2. The ages of the first 8 presidents of the United States (on the day they first took office) and the second 8 presidents are shown with bar-charts below. The ages are printed above each bar, so for example, George Washington (president number 1) was 57 years old when he took office.
    1. Which data set (1st 8 ages or 2nd 8 ages) do you think would have the larger standard deviation? Why?

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    2. The 5 number summary (min, Q1, M, Q3, max) for the first 8 presidents is min = 54, Q1 = 57, M = 57, Q3 = 59.5, and max = 61. Find the 5-number summary of the ages of the next 8 presidents.

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    3. Add a boxplot of the next eight president's ages to the plot below. Note, since Q1 = M for the first 8 presidents, the boxplot shown has no "middle bar" to indicate the location of the median. The bar for the median is thus drawn a bit longer than the edges of the box.