Chapter 12, Problem 11PT

To determine

To find: the mean, variance and standard deviation to the nearest tenth for each set of data.

Answer to Problem 11PT

The mean, variance and standard deviation is 26, 8.5 and 2.19.

Explanation of Solution

Given information:

The data is : $22,25,27,30$

Calculation: To find the mean add all data and divide it by the number of data,

  $\text{mean}=\frac{22+25+27+30}{4}$

  $\text{mean}=\frac{104}{4}\text{ [add]}$

  $\text{mean=26 [divide]}$

To find the variance, subtract each data from the mean of data and then square it and add and then divide by the numbers of data,

  $\text{variance}=\frac{16+1+1+16}{4}\text{ [subtract and square]}$

  $\text{variance}=\frac{34}{4}\text{ [add]}$

  $\text{variance}=8.5\text{ [divide]}$

To find the standard deviation, square root the variance,

  $\text{standard deviation}=\sqrt{8.5}$

  $\text{standard deviation}=2.19$