To find the variance, we first calculate the mean (\(\mu\)) of the given data:
\[
\mu = \frac{240 + 260 + 270 + 280}{4} = 262.5
\]
Next, we calculate the squared differences from the mean for each data point:
\[
(240 - 262.5)^2 = 506.25, \quad (260 - 262.5)^2 = 6.25, \quad (270 - 262.5)^2 = 56.25, \quad (280 - 262.5)^2 = 306.25
\]
Finally, the variance is the average of these squared differences:
\[
\text{Variance} = \frac{506.25 + 6.25 + 56.25 + 306.25}{4} = 16
\]