Question

A store manager is looking at past jewelry sales to determine what sizes of rings to keep in stock. The list shows the ring sizes purchased by the last ten jewelry customers. 9, 7, 2006. 5, 7. 5, 7, 8, 5, 6, 7. 5, 8 What is the variance of the data set? Round to the nearest hundredths. 0. 40 0. 72 1. 15 2. 14.

Answer 1

Using it's concept, it is found that the variance of the data-set is of 1.15.

The mean of a data-set is the sum of all observations divided by the number of observations, hence:

$E(X) = \frac{9 + 7 + 6.5 + 7.5 + 7 + 8 + 5 + 6 + 7.5 + 8}{10} = 7.15$

The variance is the sum of the differences square between each value and the mean, divided by the number of values. Hence:

$V(X) = \frac{1}{10}[(9 - 7.15)^2 + (7 - 7.15)^2 + (6.5 - 7.15)^2 + (7.5 - 7.15)^2 + (7 - 7.15)^2 + (8 - 7.15)^2 + (5 - 7.15)^2 + (6 - 7.15)^2 + (7.5 - 7.15)^2 + (8 - 7.15)^2] = 1.15$

A similar problem is given at brainly.com/question/1527299