How do I find a variance for a set of numbers {1,16,8,17,12}
I got that variance-34.2, but I'm unsure. Any help? Thanks.
math - Reiny, Sunday, January 24, 2010 at 8:16pm
look at his page.
Reiny - April, Sunday, January 24, 2010 at 8:25pm
I looked at that page and did my problem according to the example, but the answer I got wasn't even a choice. Can you help al ittle more please?
http://www.jiskha.com/display.cgi?id=1264379821
No. I thought mean was adding up the numbers and then dividing by how many numbers.
So .51+.44+.04+.01=1 divided by 4=.25
(1 + 16 + 8 + 17 + 12)/5 = 10.8
mmmmh?
where did you get your numbers from ????
To find the variance of a set of numbers, you can follow these steps:
1. Calculate the mean (average) of the set of numbers by adding all the numbers together and dividing by the total count.
Mean = (1 + 16 + 8 + 17 + 12) / 5 = 54 / 5 = 10.8
2. Subtract the mean from each number in the set and square the result. This step is called finding the squared deviations.
Squared deviation for 1 = (1 - 10.8)^2 = 99.84
Squared deviation for 16 = (16 - 10.8)^2 = 34.56
Squared deviation for 8 = (8 - 10.8)^2 = 7.84
Squared deviation for 17 = (17 - 10.8)^2 = 38.44
Squared deviation for 12 = (12 - 10.8)^2 = 1.44
3. Find the mean of the squared deviations by adding them together and dividing by the total count.
Mean of squared deviations = (99.84 + 34.56 + 7.84 + 38.44 + 1.44) / 5 = 181.12 / 5 = 36.224
4. The variance is equal to the mean of the squared deviations.
Variance = 36.224
Based on the above steps, the variance of the set {1, 16, 8, 17, 12} is 36.224, which differs from your initial calculation of 34.2. Double-check your calculations to ensure accuracy.