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.
I'll let you do the calculations.
what is the variance for the set of data 22,30,13,20,20
PsyDAG
answered10 years ago
Explain Bot
answered11 months ago
To find the variance of a set of data, follow these steps:
Step 1: Calculate the mean (average) of the data set.
To find the mean, add up all the values in the data set and divide the sum by the total number of values. In this case, add up 22 + 30 + 13 + 20 + 20 = 105, and since there are 5 values, the mean is 105/5 = 21.
Step 2: Subtract the mean from each value in the data set.
Take each value in the data set and subtract the mean from it. For example, for the first value, 22 - 21 = 1, for the second value, 30 - 21 = 9, and so on. The differences are: 1, 9, -8, -1, -1.
Step 3: Square each of the differences.
Square each of the differences calculated in Step 2. For example, 1^2 = 1, 9^2 = 81, (-8)^2 = 64, (-1)^2 = 1, and (-1)^2 = 1. The squared differences are: 1, 81, 64, 1, 1.
Step 4: Calculate the mean of the squared differences.
Add up all the squared differences from Step 3 and divide the sum by the total number of values. In this case, add up 1 + 81 + 64 + 1 + 1 = 148, and since there are 5 values, the mean is 148/5 = 29.6.
Therefore, the variance of the set of data 22, 30, 13, 20, 20 is 29.6.
Step 1: Calculate the mean (average) of the data set.
To find the mean, add up all the values in the data set and divide the sum by the total number of values. In this case, add up 22 + 30 + 13 + 20 + 20 = 105, and since there are 5 values, the mean is 105/5 = 21.
Step 2: Subtract the mean from each value in the data set.
Take each value in the data set and subtract the mean from it. For example, for the first value, 22 - 21 = 1, for the second value, 30 - 21 = 9, and so on. The differences are: 1, 9, -8, -1, -1.
Step 3: Square each of the differences.
Square each of the differences calculated in Step 2. For example, 1^2 = 1, 9^2 = 81, (-8)^2 = 64, (-1)^2 = 1, and (-1)^2 = 1. The squared differences are: 1, 81, 64, 1, 1.
Step 4: Calculate the mean of the squared differences.
Add up all the squared differences from Step 3 and divide the sum by the total number of values. In this case, add up 1 + 81 + 64 + 1 + 1 = 148, and since there are 5 values, the mean is 148/5 = 29.6.
Therefore, the variance of the set of data 22, 30, 13, 20, 20 is 29.6.
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