Standard deviation

Question

Find the standard deviation for the following sample data:

57.2

57.9

61.4

69.8

59.0

64.7

70.1

64.7

53.5

78.2

Answer 1

If you add the values together and divide by 10 (the number of values), you'll get a mean of 63.65. Then you would find the difference between each of those values and the mean and square that difference; adding up those squared differences and dividing by 9 (number of values minus 1), you get a variance of 55.30056. Then the standard deviation is the square root of the variance; that make st. dev. = 7.4364 (depending on how many slots you want to round out).