SOLUTION: A class of 15 kindergarteners had the following weights in pounds: 53 39 46 36 39 52 49 52 46 47 48 51 48 51 41 Find the mean, var

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Question 224587: A class of 15 kindergarteners had the following weights in pounds:
53 39 46 36 39 52 49 52
46 47 48 51 48 51 41

Find the mean, variance, and standard deviation.
(Points: 5)

Answer by Edwin McCravy(20056) (Show Source):
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A class of 15 kindergarteners had the following weights in pounds: 53 39 46 36 39 52 49 52 46 47 48 51 48 51 41 Find the mean, variance, and standard deviation. (Points: 5) List them in a column with heading X, add them and divide by the number of numbers, which is 15. That is the mean: X 53 39 46 36 39 52 49 52 46 47 48 51 48 51 41 --- 15)698 _ --- X = 46.5333�� Subtract that mean from each of the numbers and place in another column headed with X-X _ X X-X 53 -6.4666... 39 -7.5333... 46 -0,5333... 36 -10.5333... 39 -7.5333... 52 5.4666... 49 2.4666... 52 5.4666... 46 -0.5333... 47 0.4666... 48 1.4666... 51 4.4666... 48 1.4667... 51 4.4666... 41 -5.5333... --- 15)698 _ --- X = 46.5333�� _ The mean = X = 46.5333... Now square all those in that list and place them _ in a third column headed (X-X)�, add that column and divide by one less than 15, or 14 _ _ X X-X (X-X)� 53 -6.4666... 41.81777... 39 -7.5333... 56.75111... 46 -0.5333... .28444... 36 -10.5333... 110.95111... 39 -7.5333... 56.75111... 52 5.4666... 29.88444... 49 2.4666... 6.08444... 52 5.4666... 29.88444... 46 -0.5333... 0.28444... 47 0.4666... 0.21777... 48 1.4666... 2.15111... 51 4.4666... 19.95111... 48 1.4667... 2.15111... 51 4.4666... 19.95111... 41 -5.5333... 30.61777... --- ------------ 15)698 14)407.73333... _ --- ------------ X = 46.5333�� s�=29.12380952... s� is the variance = 29.12380952... s is the standard deviation = ... Edwin