Normal Distribution Curve Lesson

12.4 Normal Distribution

Finite Math

EQ: Monday, April 15, 2024

• What is a percentile?

• What is a Normal Distribution Curve?

• How do I find the percent of a population within increments of standard deviations?

• What is the 68-95-99 Rule?

Percentile

The percentage of values lower than the value of interest over the total.

17th

Kevin Hart

1

Daniel Radcliffe

Jack Black

Tom Cruise

Mark Wahlberg

Robert Downey Jr.

Johnny Depp

Brad Pitt

Ryan Gosling

Bradley Cooper

Will Smith

Will Ferrell

Jason Segel

Vince Vaughn

2

3

4

5

6

7

8

9

10

11

12

13

14

Multiple Choice

Find the percentile for Will Ferrell.

• 79 percentile

• 86 percentile

• 54 percentile

• 14 percentile

Multiple Choice

Find the percentile for Daniel Radcliff.

• 7 percentile

• 14 percentile

• 93 percentile

• 28 percentile

Multiple Choice

Find the percentile for Vince Vaughn.

• 93 percentile

• 100 percentile

• 7 percentile

• 28 percentile

Multiple Choice

Find the percentile for Kevin Hart.

• 0 percentile

• 1 percentile

• 7 percentile

• 28 percentile

Normal Distribution Curve

​100%
of the
Population

Normal Distribution Curve

50%

50%

Drawing a Normal Distribution

​Does not
touch the
horizontal
axis

Drawing a Normal Distribution

Concave UP

Drawing a Normal Distribution

Symmetrical

Drawing a Normal Distribution

mean
with 3 SD on each side

Labelling

For the data set with a mean of 9 and a standard deviation of 2, label the axis.

Drag labels to their correct position on the image

11

13

9

5

15

3

7

​Normal Distribution Curve

Shows the percentage of the population by section

Multiple Choice

Give the percent in the section with the QUESTION MARK.

• 68 %

• 34 %

• 99 %

• 95 %

​Half of 68% = 34%

Multiple Choice

Give the percent in the section with the QUESTION MARK.

• 13.5 %

• 34 %

• 68 %

• 95 %

​Half of 95 - 68
= (95-68)/2
= 27 / 2
= 13.5%

Multiple Choice

Give the percent in the section with the QUESTION MARK.

• 13.5 %

• 34 %

• 2.35 %

• 10%

​Half of 99.7 - 95
= (99.7- 95)/2
= 4.7 / 2
= 2.35%

One hundred seniors took the SAT at a particular site. The mean SAT score of 500 with a standard deviation of 100.

If your score is 700, how many seniors scored lower than you?

​200 300 400 500 600 700 800

2.5 %

2.5 %

100 - 2.5 = 97.5

95%

Multiple Choice

Find the percentage of the shaded regions in the normal distribution curve.

• 18.5

• 28.5

• 7.5

• 42.5

​Cheat Sheet