Step 1: Calculate the Variance ($\sigma^2$). The formula for variance for grouped data is: $$\sigma^2 = \frac{\sum f(x - \bar{x})^2}{\sum f}$$ From the provided table, $\sum f(x - \bar{x})^2 = 2560.32$ and $\sum f = 50$. Substitute the values into the formula: $$\sigma^2 = \frac{2560.32}{50}$$ $$\sigma^2 = 51.2064$$ Step 2: Calculate the Standard Deviation ($\sigma$). The standard deviation is the square root of the variance: $$\sigma = \sqrt{\sigma^2}$$ Substitute the calculated variance: $$\sigma = \sqrt{51.2064}$$ $$\sigma \approx 7.156$$ The variance is $\boxed{51.2064}$ The standard deviation is $\boxed{7.156}$ Send me the next one 📸