Question

Eight randomly selected customers at a local grocery store spent the following amounts on groceries in a single visit: $216, $184, $35, $92, $142, $175, $9, and $57. Let yi denote the amount spent on groceries by a single customer in a single visit. Find the following (give the answers without commas):

a. ∑y
b. (∑y)^2
c. ∑y^2

Answer 1

a) 910

b) 828100

c) 144320

Explanation:

a. ∑y

This is the sum of all values of y. So

`\sum y = 216 + 184 + 35 + 92 + 142 + 175 + 9 + 57 = 910`

b. (∑y)^2

This is the square of the sum, so the square of 910, that we found in the previous item.

910² = 828100

c. ∑y^2

This is the sum of the squares of each amount spent. So

`\sum y^2 = 216^2 + 184^2 + 35^2 + 92^2 + 142^2 + 175^2 + 9^2 + 57^2 = 144320`