What is the sample variance of this set of numbers 1 2 3 4 5

What is the sample variance of this set of numbers? {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

A. 1.7 B. 5.7 C. 7.7 D. 9.2

Solution

Step 1:Add them up:
1+ 2+ 3+ 4+ 5+ 6+ 7+ 8+ 9+ 10 = 55

Step 2: Square your answer:
55 × 55 = 3025
…and divide by the number of items. We have 10 items in our example so:
3025 / 10 = 302.5
Set this number aside for a moment.

Step 3: Take your set of original numbers from Step 1, and square them individually this time:
1^2+2^2+3^2+4^2+5^2+6^2+7^2+8^2+9^2+10^2 = 385

Step 4: Subtract the amount in Step 2 from the amount in Step 3.
385 - 302.5= 82.5
Set this number aside for a moment.

Step 5: Subtract 1 from the number of items in your data set. For our example:
10 – 1 = 9

Step 6: Divide the number in Step 4 by the number in Step 5. This gives you the variance:
82.5/ 9 = 9.1667 ~ 9.2