Find the mean first = sum of scores/number of scores
Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.
Standard deviation = square root of variance
I'll let you do the calculations.
The test scores for a math class are shown below.
81,84,82,93,81,85,95,89,86,94
What is the standard deviation of the data set? Roun your answer to the nearest tenth
4.9
5.5
5.3
5.1
2 answers
Sum = 870
Mean = 870/10 = 87
X Mean X - Mean X - Mean ^ 2
81 87 -6 36
81 87 -6 36
82 87 -5 25
84 87 -3 9
85 87 -2 4
86 87 -1 1
89 87 2 4
93 87 6 36
94 87 7 49
95 87 8 64
Take the sum of all of these ^^^ and you get 264
Divide this by the # of terms, 10, and get 26.4
Your variance = 26.4
The standard deviation is the sqr root of 26.4
This is approximately 5.1
Have a great day
Mean = 870/10 = 87
X Mean X - Mean X - Mean ^ 2
81 87 -6 36
81 87 -6 36
82 87 -5 25
84 87 -3 9
85 87 -2 4
86 87 -1 1
89 87 2 4
93 87 6 36
94 87 7 49
95 87 8 64
Take the sum of all of these ^^^ and you get 264
Divide this by the # of terms, 10, and get 26.4
Your variance = 26.4
The standard deviation is the sqr root of 26.4
This is approximately 5.1
Have a great day
4 answers