Warmup

Define.

1. mean

2. median

3. mode

4. range

5. maximum

6. minimum

Lesson 11 Measures of Central Tendency

Objective #2: Calculate measures of central tendency (mean, median, and mode).– Mean (a.k.a “average”): Add and Divide

– Median (a.k.a “middle”): Order and pick middle #

– Mode (a.k.a “most”): Find number repeated the most

ANSWERSDefine each of the following terms.1. mean average

2. median middle of a group when put in sequential order

3. mode most frequently occurring

4. range maximum minus the minimum

5. maximum highest value

6. minimum lowest value

Video Lessons

Ten Marks (Scroll down to the video screen for central tendency.)

Khan Academy Video

Process

Mean

Step 1 – Add up all of the numbers given.

Step 2 – Divide the sum by the total number of numbers added.

Process

Median

Step 1 – Put numbers in order from least to greatest.

Step 2 – Locate the middle number– If there is an exact middle number, that is the median.

– If there are two numbers in the middle, add them together and divide by 2. (Find their mean)

Process

Range

Step 1 – Locate largest and smallest number

Step 2 – Subtract smaller number from larger number (biggest number minus smallest number.)

EXAMPLE 2Identify the minimum, maximum, range, and median for Dallas and Houston for the number of months having less than 3.5” rainfall.

Seven students in the seventh grade took a quiz. They scored the following:

30, 30, 24, 24, 27, 37, 24.

1. To find the mean, add all of the numbers, then divide by number of addends. (number of numbers added)

 

24 + 24 + 24 + 27 + 30 + 30 + 37 = 196

196 ÷ 7 = 28

The mean is 28 points.

Seven students in the seventh grade took a quiz. They scored the following:

30, 30, 24, 24, 27, 37, 24.

2. To find the median, arrange that data in order from least to greatest, then find the middle number.

  24, 24, 24, 27, 30, 30, 37

The median is 27.

 

Seven students in the seventh grade took a quiz. They scored the following:

30, 30, 24, 24, 27, 37, 24.

3. To find the mode, find the number that occurs most often.

The mode is 24.

 

Seven students in the seventh grade took a quiz. They scored the following:

30, 30, 24, 24, 27, 37, 24.

4. To find the range, subtract the greatest number and the least number. This will show the spread of the data.

 

37 – 24 = 13

The range is 13 points.

 

Find the mean, median, and mode(s) of the data.

8, 12, 15, 17, 18, 26

186, 144, 201, 164, 182, 164

ANSWER 16, 16, no mode

ANSWER 173.50, 173, 164

ANSWER about $17.71

The monthly charge for seven dial-up internet service providers are listed. What is the mean price? $10, $22, $17, $11, $16, $23, $25

Find the mean, median, mode, range, maximum, and minimum of each set.

1. {1, 2, 2, 3, 4, 5, 11}

2. {7, 6, 1, 7, 4}

3. {7, 10, 3, 2, 5, 12}

Find the mean, median, mode, range, maximum, and minimum of each set.

1. {1, 2, 2, 3, 4, 5, 11}mean:4 median:3 mode:2 range:10 maximum:11 minimum:1

2. {7, 6, 1, 7, 4}mean:5 median:6 mode:7 range:6 maximum:7 minimum:1

3. {7, 10, 3, 2, 5, 12}mean:6.5 median:6 mode:none range:10 maximum:12 minimum:2

Extending the Learning

How will new values affect the measures of central tendency?

Select your numbers and show the measures.