1. Class Census: Using Percentages, Range, Averages, and Frequency Class Census: Using Percentages, Range, Averages, and Frequency

2. Class Census Steps to take before we begin… On your note card write the following: –Your height (in inches) –The name of the elementary school you most recently attended –The month of your birthday –Your favorite number between 1 and 25 Have one person collect all of the note cards

3. Average  The average, or mean, is…  the sum of all the numbers divided by the total number of measures Sum Number of measures Average = Avg 4 numbers = N 1 + N 2 + N 3 + N 4 4

4. Average A survey was conducted using the car insurance rates of five different people. 1$324.00 2$245.00 3$311.00 4$180.00 5$201.00 Survey Results

5. Average What is the average cost of car insurance for these five people? 1$324.00 2$245.00 3$311.00 4$180.00 5$201.00 Survey Results Average Cost = Sum Number of measures Average = $324 + $245 + $311 + $180 + $201 5 Average Cost = $1261 5 Average Cost = $252.20

6. How tall is the average student in this class?

7. Range The RANGE is how broad the set of numbers are. Find the range by subtracting the smallest value from the greatest Range = MAX value – MIN value The “MAX” is the “maximum” or largest number The “MIN” is the “minimum” or smallest number

8. Range What is the range of monthly car insurance costs? 1$324.00 2$245.00 3$311.00 4$180.00 5$201.00 Survey Results Range = MAX - MIN Range = $311.00 - $180.00 Range = $131.00

9. What is the range of student heights in this class?

10. Percentage Calculating a percentage is a method of expressing a number as a proportion of 100. (a proportion per hundredth) ‘Per cent’ means ‘per one-hundred’ For example, 56% = 56/100 =.56 17.2% = 17.2/100 =.172 8.25% = 8.25/100 =.00825 110% = 110/100 = 1.10

11. Percent When solving for a certain percent of a number we use the equation… Part / Whole  Percent / 100

12. Percent What is 28% of 147? Part = Percent * Whole Part = Percent * Whole P = % * W P = % * W 28% =.28 and 147 is the whole, we need to find the part. P =.28 * 147 P =.28 * 147 P = 41.16 P = 41.16 28100?147 = 28100?147 =

13. Percent If person 2 is offered a 20% discount, how much will he save? If person 3 changes to a new rate of $290.00 per month, what percent of change is this? 1$324.00 2$245.00 3$311.00 4$180.00 5$201.00 Survey Results P = % * W Discount = % * (Cost) Discount =.20 * 245.00 Discount = $49.00 % = P / W % = Discount / Old rate Discount = Old rate – New rate Discount = $311.00 - $290.00 Discount = $21.00 % = $21.00 / $311.00 % =.0675 = 6.75%

14. What percent of the class is born in September?

15. Frequency Frequency is the number of times a value occurs in a data set. All we have to do to find the frequency is count!

16. Frequency Eight students gave their favorite color Here are the color frequencies –Red 2 –Green 3 –Pink 1 BobbyGreen SusanPink RickGreen AndyBlue JillRed JoeRed AmandaGreen GilbertPurple

17. Organize the data for the names of the elementary schools that the class attended. Which occurs with the greatest frequency ?

18. What percent of the class attended the most popular elementary school?

19. Additional Questions What is the range of favorite numbers? What is the average favorite number? Which favorite number has the highest frequency? What percentage of the students have single-digit (1-9) favorite numbers?