Question

What is the variance of the following data? If necessary, round your answer to two decimal places. 17, 13, 13, 22, 11, 20

Answer 1

Variance is the standard deviation squared but we're not going to use that now. Let's first calculate the mean:

mean = (17+13+13+22+11+20)/6 = 16.

Now for each value, let's see how far it is from this mean. We'll square these distances and average them. That's our variance.

17 distance 1 squared = 1
13 distance 3 squared = 9
13 distance 3 squared = 9
22 distance 6 squared = 36
11 distance 5 squared = 25
20 distance 4 squared = 16

Now average these outcomes:

variance = (1+9+9+36+25+16)/6 = 16.

So the variance by coincidence is the same as the mean.

Answer C is your answer.