Step 1 to Calculate the Variance: Find the Mean

To find the variance of Average_Pulse:

Calculate the mean:

(80 + 85 + 90 + 95 + 100 + 105 + 110 + 115 + 120 + 125) / 10 = 102.5

The mean is 102.5.

Step 2: For Each Value – Find the Difference From the Mean

Calculate the difference from the mean for each value:

80 – 102.5 = -22.5
85 – 102.5 = -17.5
90 – 102.5 = -12.5
95 – 102.5 = -7.5
100 – 102.5 = -2.5
105 – 102.5 = 2.5
110 – 102.5 = 7.5
115 – 102.5 = 12.5
120 – 102.5 = 17.5
125 – 102.5 = 22.5

Step 3: For Each Difference – Find the Square Value

Square each difference:

(-22.5)^2 = 506.25
(-17.5)^2 = 306.25
(-12.5)^2 = 156.25
(-7.5)^2 = 56.25
(-2.5)^2 = 6.25
(2.5)^2 = 6.25
(7.5)^2 = 56.25
(12.5)^2 = 156.25
(17.5)^2 = 306.25
(22.5)^2 = 506.25

Note: Squaring the differences gives us the total spread.

Step 4: The Variance is the Average Number of These Squared Values

Sum the squared values and find the average:

(506.25 + 306.25 + 156.25 + 56.25 + 6.25 + 6.25 + 56.25 + 156.25 + 306.25 + 506.25) / 10 = 206.25

Thus, the variance is 206.25.