Relative, cumulative: frequency

Frequency Distribution Table

Percentile

The pth percentile of a distribution is the value such

that p percent of the observation fall at or below it.

Standardized test scores

Roberto received his ACT score and it says he’s in the 80th percentile. What does

that mean?

80% of the people who took the test earned scores that were less than or equal to your

score.

Frequency Distribution TableFrequency

distribution A tabulation of the number of individuals in each category on the scale of measurement.

Age of US presidents at their respective

inauguration

Presidential Ages at Inauguration

1. Get the range of the ages of the presidents42 to 69

2. Decide on what class size to use

Class width of 5 from 40-44, 45-49...

3. Construct your frequency distribution table

Class size frequency

Relative frequency

Cumulative

frequency

Relative Cumulative Frequency

40-44 2 2/43 = 4.7% 2 2/43 = 4.7%

45-49 6 6/43 = 14.0% 8 8/43 = 18.6%

50-54 13 13/43 = 30.2% 21 21/43 = 48.8%

55-59 12 12/43 = 27.9% 33 33/43 = 76.7%

60-64 7 7/43 = 16.3% 40 40/43 = 93.0%

65-69 3 3/43 = 7.0% 43 43/43 = 100%

Total 43

FDT: Ages of the presidents at inauguration

Constructing your OGIVEOGIVE: Relative Cumulative Frequency Graph

Was Bill Clinton a young president?

According to our ogive, it

shows that Clinton’s age

places him at the 10% RCF

mark. Therefore Clinton

was younger than about

90% of all the US presidents

based on his inauguration

age.

Let’s find the distribution of the height of all the students in room 34 during this period.

Your turn!Height of 2011-2012 AP Statistics Students of BHS

Range:Class

width and size:

73 - 59 = 14

Width: 3Size: 58-60; 61-63; 64-66; 67-69; 70-72; 73-75

Class size frequency

Relative frequency

Cumulative

frequency

Relative Cumulative Frequency

58-60 2 2/26 = 7.7% 2 2/26 = 7.7%

61-63 8 8/26 = 30.8% 10 10/26 = 38.5%

64-66 4 4/26 = 15.4% 14 14/26 = 53.8%

67-69 6 6/26 = 23.1% 20 20/26 = 76.9%

70-72 4 4/26 = 15.4% 24 24/26 = 92.3%

73-75 2 2/26 = 7.7% 26 26/26 = 100%

Total 26

FDT: Height of 2011-2012 AP Statistics Students of BHS

Ogive: Height of 2011-2012 AP Statistics Students of BHS

Vocabulary Summary

Individuals variablescategorical

quantitative

Dotplots

Stemplotshistogram

center

spread

shape skewness

outlier

ogive

FDT

Individualspercentile

Statistical toolsDescribing SOCS and skewness

Constructing dotplots and stemplots

Describing the SOCS of your distribution

Creating histogram

Generating histogram using graphing calculator

Organizing data by FDT

Constructing ogive and finding percentile using ogive.