Data Analysis: Measures of Central Tendency

Objective: To find and interpret the mean, median, and mode of a set of data.

Open books to page 711.

(1.) Measures of Central Tendency **

Definition: Measures of central tendency are used to describe sets of data because they represent a centralized or middle value.

NOTE: Mean, Median, and Mode are all measures of central tendency.

(2.) Mean **

Definition: The sum of a set of numbers divided by the number of numbers in the set.

Example:

Set = { 5, 8, 10, 12, 15 }

Mean = (5 + 8 + 10 + 12 + 15) / 5 = 10

(2.) Median **Definition: The median of a set of data is the

middle number of the set, when the numbers are arranged in numerical order.

Example:{ 5, 8, 10, 12, 15 } Median = 10{ 2, 5, 7, 8 } Median = (5+7)/2 = 6

NOTE: If there an even number of numbers in a set, then the median is the average of the two middle numbers.

(3.) Mode and (4.) Frequency **

Mode: The mode of a set of data is the number with the highest frequency (the number that appears the most)

NOTE: There can be more than one mode.

Frequency: The number of times a number occurs.

NOTE: The frequency of a set of data is the number of elements (numbers) in the set.

Using the TI 83/84 *

To find the mean and median of a set of data:

1. Enter the data into L1 ([stat][edit] L1)

2. Find the stats ([stat][calc] OneVarStats [Enter])

3.

Find the mean and median of : 1, 3, 4, 8, 14, 20

frequencyn

medianMed

meanx

Homework

Page 712, #1 – 14 (ALL)

Due tomorrow