A B C D E
Homework

Problem H2

First you'll need to find the mean by adding all the values and dividing by 9:

1 + 4 + 10 + 4 + 4 + 6 + 7 + 10 + 4 = 50 / 9 = 5.6 (to one decimal place)

We will use 5.6 for the mean. Here is the table for calculating the MAD:

	Number of Coins in Stack (x)		Deviation from the Mean (x - 5.6)		Absolute Deviation from the Mean |x - 5.6|
	1 -4.6 4.6 4 -1.6 1.6 10 +4.4 4.4 4 -1.6 1.6 4 -1.6 1.6 6 +0.4 0.4 7 +1.4 1.4 10 +4.4 4.4 4 -1.6 1.6 ______ ______ ______ 50 0 21.6

The MAD is approximately 21.6 / 9 = 2.4 (to one decimal place). (If you are using fractions, the exact answer is 194/81.)

Here is the table for calculating the variance:

	Number of Coins in Stack (x)		Deviation from the Mean (x - 5.6)		Squared Deviation from the Mean |x - 5.6|2
	1 -4.6 21.16 4 -1.6 2.56 10 +4.4 19.36 4 -1.6 2.56 4 -1.6 2.56 6 +0.4 0.16 7 +1.4 1.96 10 +4.4 19.36 4 -1.6 2.56 ______ ______ ______ 50 0 72.24

The variance is 72.24 / 9 = 8.0 (to one decimal place). (If you were using fractions, the exact answer is 650/81.)

The standard deviation is the square root of 8, which is 2.8 (to one decimal place). (The exact fractional answer, the square root of 650/81, cannot be expressed by a rational number, since 650 is not a square number.)

The results of Problems H1 and H2 suggest that the data in Problem H2 have greater variation about the mean than the data in Problem H1.

<< back to Problem H2

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