Find the range, variance, and standard deviation for the

Problem 2DA

Find the range, variance, and standard deviation for the data selected in Exercise 1. Reference Exercise: From the Data Bank, choose one of the following variables: age, weight, cholesterol level, systolic pressure, IQ, or sodium level. Select at least 30 values, and find the mean, median, mode, and midrange. State which measurement of central tendency best describes the average and why.

                                                              Step by step solution

Step 1 of 2

Let’s consider the 30 values of  IQ from the Data Bank:

118,105,115,108,106,111,99,106,111,109,115,114,101,109,98,103,103,99,110,108,112,106,116, 121,122,103,119,116,105,123.

Mean, also known as the arithmetic average, is found by adding the values of the data and dividing by the total number of values.

Median is the midpoint of the data array, ie;

MD =

The value that occurs most often in a data set is called the Mode, ie; the values 103 and 106 both occur 3 times, the modes are 103 and 106. The data set is said to be bimodal

The midrange is defined as the sum of the lowest and highest values in the data set, divided by 2. The symbol MR is used for the midrange.

The mean central tendency describes the average because the data contains no outliers.