### Home > CCA2 > Chapter 9 > Lesson 9.2.2 > Problem9-65

9-65.

In an effort to determine the amount of food a male yellow-billed magpie eats in a day, a sample of $5$ birds from pet stores was observed. The birds ate the following amount of food: $60, 60, 50, 40,$ and $50$ grams. Find the mean and standard deviation weight of food in this sample. Do the computations step by step, without using the “standard deviation” function on your calculator, as in problem 9-52.

mean: $52$

Sample standard deviation:

$\sqrt{\frac{(60-52)^2+(60-52)^2+(50-52)^2+(40-52)^2+(50-52)^2}{5-1}}$

Note that we divide by $n - 1$ because this is a sample.