1. Warm Up Make a Box-and-Whisker plot for the two sets of data below
I can find standard deviation and interpret normal curves
Warm Up
Make a Box-and-Whisker plot for the two sets of data below
A: 48, 44, 56, 25, 97,94, 82, 80
B: 50, 68, 50, 88, 102, 50, 75, 80
2. If the data represents salaries of two competing companies, which company would you work for any why?

2. Homework Questions

3. Work Sample
Student Name: Legal Name Student ID#: Grade: Date Task Assigned: May 6, 2015 Page 2 – Name, Ms. Freeman, May 6

4. Normal Distribution (Bell) Curve
A normal distribution curve (also known as a bell curve) is symmetrical, bell-shaped curve defined by the mean and standard deviation of a data set.

5. Bell Curve

6. Bell Curve
μ-2σ
μ-σ
Mean μ
μ+σ
μ+2σ

7. 68% of data falls within 1 standard deviation of the mean
Bell Curve
68% of data falls within 1 standard deviation of the mean
μ-2σ
μ-σ
Mean μ
μ+σ
μ+2σ
68%

8. 95% of data falls within 2 standard deviations of the mean
Bell Curve
95% of data falls within 2 standard deviations of the mean
μ-2σ
μ-σ
Mean μ
μ+σ
μ+2σ
95%

9. Bell Curve
μ-2σ
μ-σ
Mean μ
μ+σ
μ+2σ
99.7%

10. 34%
34%
13.6%
13.6%
Because the bell curve is perfectly symmetrical, we can break down the percent of data that falls in each section.

11. Things that often fall in a Normal Distribution
Test Scores
Height
Size of things produced by machines
Errors in measurement
Blood pressure

12. Analyzing Data – Test Scores
Suppose test scores on the last unit test followed a normal distribution with a mean of 75 and a standard deviation of % of students would have scored between what two values?
Between 65-85 75 85 95 65 55

13. Analyzing Data – Test Scores
Suppose test scores on the last unit test followed a normal distribution with a mean of 75 and a standard deviation of % of students would have scored between what two values?
Between 65-85

14. Height of 6th Graders
The average height of 6th graders at Beverly Cleary Middle School is 60 inches with a standard deviation of 4 inches. What percent of students are between 52 and 68 inches?
95% 60 64 68 56 52

15. Height of 6th Graders 95% of students are between 52 and 68 inches
The average height of 6th graders at Beverly Cleary Middle School is 60 inches with a standard deviation of 4 inches. What percent of students are between 52 and 68 inches?
95% of students are between 52 and 68 inches
inches

16. Weight of 4th Graders 50-34=16%
The average weight of a 4th grader at Lynnwood Elementary is 72 pounds, with a standard deviation of 12 pounds. What percent of 4th graders weigh above 84 pounds?
50-34=16% 72 84 96 60 48
50%
34%

17. BREAK!

18. Standard Deviation The symbols:
𝜎= 1 𝑁 𝑖=1 𝑁 ( 𝑥 𝑖 −𝜇) 2
The symbols:
𝜎 (read sigma) means standard deviation
𝜇 (read mu) means mean (or average)
𝑚𝑒𝑎𝑛𝑠 𝑠𝑢𝑚

19. Standard Deviation on the Calculator
Example: 10, 6, 9, 12, 4, 7 Clear your calculator: Press 2nd Enter in your data Press STAT ENTER Type in your data points, pressing enter between each one

20. Standard Deviation on the Calculator
Calculate Standard Deviation
Press STAT
Right arrow until CALC is highlighted at the top
Select option 1: 1-Var Stats
Press ENTER
Continuing pressing ENTER until data appears (3 more times)

21. Standard Deviation on the Calculator
Interpret the calculations 𝑥  Mean 𝜎𝑥  Standard Deviation N  number of data points

22. Find the mean and standard deviation for each data set
B: 50, 68, 50, 88, 102, 50, 75, 80
𝜇=65.75
𝜎=24.46
𝜇=70.375
𝜎=18.29

23. Normal Distribution Homework