Sir I have the follwong tables, and need to show the Standard Deviation, the formula is also enclosed.

Sir I have the follwong tables, and need to show the Standard Deviation, the formula is also enclosed.The tables are correct but I am having trouble figuring out the formula, please see below-3. A company had 80 employees whose salaries are summarized in the frequency distribution below. Find the standard deviation. Find the standard deviation of the data summarized in the given frequency distribution.Salary Number of Employees5,001 -10,000 1110,001 – 15,000 13 15,001 – 20,000 2020,001 – 25,000 1725,001 – 30,000 13 salaries frequencies class midpoint X f*x f*x^25001-10000 11 7500.5 82505.5 XXXXXXXXX 810001-15000 13 12500.5 162506.5 XXXXXXXXXX 15001-20000 20 17500.5 350010 XXXXXXXXXX 20001-25000 17 22500.5 382508.5 XXXXXXXXXX 25001-30000 13 27500.5 357506.5 XXXXXXXXXX totals 74 (NNN) NNN-NNNNXXXXXXXXXXX Variance σ 2 =∑x2 f/n – ( ∑xf/n) 24. The heights of a group of professional basketball players are summarized in the frequency distribution below. Find the standard deviation.Height (in.) Frequency70-71 472-73 974-75 1876-77 1178-79 980-81 482-83 1 heights frequency class midpoint x f*x f*x^270-71 4 70.5 282 1988172-73 9 72.5 652.5 47306.2574-75 18 74.5 1341 99904.576-77 11 76.5 841.5 64374.7578-79 9 78.5 706.5 55460.2580-81 4 80.5 322 2592182-83 1 82.5 82.5 6806.25totals 56 4228 319654 Variance σ 2 =∑x2 f/n – ( ∑xf/n) 2