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2.1 Graphs and Tables for Categorical Data

Objectives:By the end of this section, I will beable to…

1) Construct and interpret a frequency distribution and a relative frequency distribution for qualitative data.

2) Construct and interpret bar graphs and Pareto charts. 3) Construct and interpret pie charts.

Frequency: number of times an observation occurs

Frequency Distribution: table listing all the values and frequency of a variable

Frequency Distributions

LawyerProfessional AthleteMilitary OfficerDoctorScientist

What career do you think is the MOST prestigious?

Frequency Distribution

CAREER

FREQUENCYLawyer

Pro. AthleteMilitary

OfficerDoctor

Scientist

Relative Frequency: frequency divided by the sample size

RELATIVE Frequency

Frequency Distribution

CAREER

FREQUENCYLawyer

Pro. AthleteMilitary

OfficerDoctor

Scientist

Rel. Freq

Using the regular FREQUENCY

Using the RELATIVE FREQUENCY

Bar GraphPARETO CHART: bar graph when the bars are put in order from highest to lowest.

Pie Charts

Common Statistical Graphs

Common Statistical Graphs

Who is that guy?What does he have to do with Statistics?

Its Julius Caesar!And he developed the Caesar Cipher.It was used to encode messages.

So what? Well we can use statistics to DECODE messages.

Frequency of Letters

Decode this Message

“Zcdmpc G bgqamtcpcb rfc kgpyajcq md qagclac, kyega psjcb rfc umpjb.”- Ugjjgyk Iykiuykzy

“Before I discovered the miracles of science, magic ruled the world.- William Kankwamba

Decode this Message

“M wipp mgi mr xli amrxiv, M wipp jmvi mr lipp, M eq e lywxpiv fefc, M’pp wipp aexiv xs e aipp” Nec D

“I sell ice in the winter, I sell fire in hell, I am a hustler baby, I’ll sell water to a well” Jay Z

“P nva alzalk mvy hpkz. P ruvd ihyhjr nva alzalk mvy hpkz. Aolyl'z uv zohtl pu ilpun alzalk mvy hpkz. Pa'z hu ptwvyahua aopun."

-Qvl Ipklu

"I got tested for AIDS. I know Barack got tested for AIDS. There's no shame in being tested for AIDS. It's an important thing.“

Joe Biden