Estimate mean and variance from seven raw values

These are seven raw observations, not a frequency table. $\sum x=426$ and $\sum x^2=26268$. Therefore $\bar x=426/7=60.85714286\approx60.9$ and $\begin{aligned}&s^2\\ & =\frac1{6}\left(26268-\frac{426^2}{7}\right)\\ & =\frac{400}{7}\approx57.1.\end{aligned}$ The denominator is $n-1=6$.

Press STAT → 1:Edit. Highlight L1 and press CLEAR to remove old entries, then enter 52, 50, 65, 59, 70, 63, 67 in L1. Choose STAT → CALC → 1:1-Var Stats, set List L1 with no frequency list, and Calculate → ENTER. The screen gives $n=7$, $\bar x=60.85714286$, $\sum x=426$, $\sum x^2=26268$, $S_x=7.55928946$, $\sigma_x=6.998542122$, minimum 50 and first quartile 52. Retrieve VARS → 5:Statistics → 3:Sx and square it with x² → ENTER: $S_x^2=57.14285714$. Use unrounded stored values.