Juana weighed a sample of 12 jumbo eggs. Here are their weights (in grams): \begin{aligned} &67, 67, 68, 69, 69, 70, \\ &71, 71, 71, 72, 72, 73 \end{aligned} 67,67,68,69,69,70, 71,71,71,72,72,73 The mean is \bar x =70 x ˉ =70x, with, \bar, on top, equals, 70 grams. Which of these formulas gives the standard deviation?