Working with Quantitative Data

Measures of Central TendencyMean, Median, Mode

Measures of Central Tendency

• Mean, median and mode are called measures of central tendency

• They provide a one number summary of set of numbers

• Since they can only provide one number to represent the entire data set, they target the center, but in different ways

How do you calculate a mean?

The following are the ages (in years) of all eight employees of a small company:53 32 61 27 39 44 49 57

Find the mean age of these employees.

How do you find a median?

The following data give the prices (in thousands of dollars) of seven houses selected from all houses sold last month in a city.

312 257 421 289 526 374 497

Find the median.

How do you find a median?Profits of 12 Companies for 2008

Company 2008 Profits(billions of dollars)

Merck & Co. 8IBM 12Unilever 7Microsoft 17Petrobras 14Exxon Mobil 45Lukoil 10AT&T 13Nestle 17Vodafone 13Deutsche Bank 9China Mobile 11

The following table gives the 2008 profits (rounded to billions of dollars) of 12 companies selected from all over the world.

Find the median of these values.

How do you identify the mode(s)

The following data give the speeds (in miles per hour) of eight cars that were stopped on I-95 for speeding violations.

77 82 74 81 79 84 74 78

Find the mode(s) of these values.

How do you identify the mode(s)

For the table in Question 3 on the previous page, find the mode(s) of these values.

Profits of 12 Companies for 2008Company 2008 Profits

(billions of dollars)

Merck & Co. 8IBM 12Unilever 7Microsoft 17Petrobras 14Exxon Mobil 45Lukoil 10AT&T 13Nestle 17Vodafone 13Deutsche Bank 9China Mobile 11

Pocket CamcordersBrand Model Price Overall

ScoreLCD Size (in.)

Battery life (min.)

JVC Picsio GC-FM2 180 54 3.0 75

Kodak Play Sport Zx3 135 54 2.0 84Sony Bloggie MHS-SM5 170 53 2.4 47Panasonic HM-TA1 165 53 2.0 61Sony Bloggie MHS-PM5/VC 120 52 2.4 84

Toshiba Camileo S20 125 50 2.9 117Samsung HMX-E10 150 50 2.8 52Creative Vado HD VF0624 150 49 2.0 160

Pocket Camcorders – Mean, Median, Mode

Mean Median Mode(s)

Size (oz.)

Price Paid ($)

Cost/Serving ($)

Calories/Serving

Fat/Serving (grams)

Sodium/Serving (mg.)

Complete the above table using your calculator

Buffalo Wings ----- Per Serving -----

Product Size(oz.)

Price($)

Cost($)

Cal. Fat(gm.)

Sodium(mg.)

Very Good

Bell & Evans 16 6.99 2.33 170 10 350

T.G.I. Fridays 27 9.25 1.54 180 11 1,030Perdue Lightly Breaded 32 7.70 1.28 180 11 720Café W (Walgreens) 10 3.08 1.23 160 11 830Good

Tyson Any’tizers Buffalo Style Hot 28 7.31 1.22 190 13 760

Weaver Flats 20 5.93 1.48 170 11 570Great Value (Walmart) 32 6.59 0.82 140 9 400

Buffalo Wings – Mean, Median, Mode

Mean Median Mode(s)

Size (oz.)

Price Paid ($)

Cost/Serving ($)

Calories/Serving

Fat/Serving (grams)

Sodium/Serving (mg.)

Download the calculator on rtnj.blackboard.com and complete the following table for homework.