A dataset of n=10n = 10n=10 observations has ∑i=110xi=150\sum_{i=1}^{10} x_i = 150∑i=110xi=150 and ∑i=110xi2=2500\sum_{i=1}^{10} x_i^2 = 2500∑i=110xi2=2500. What is the variance σ2\sigma^2σ2?
505050
252525
250250250
100100100