The Manga Guide to Statistics

1. Probability Density Function

In statistics, we often

use the term probability.

We say, "the

probability of

blah blah is

smaer than

0.05."

Today, I wi teach

you what you nd

to know to obtain

that "probability of

blah blah."

"Mr. Yamamoto's

kind of cute!"

He is not cute

at a. My prince

charming is

Mr. Igarashi...

Rui?

Soy! Is the probability

you are talking about the

same as the probability

I often hear in weather

forecasts?

Exactly.

Today's

topic is

a lile

abstract.

But study hard. What you

are going to learn today

is used in many areas of

statistics.

I' try.

STARE...

Abstract?!

Oh, no!

Rui

82 Chapter 5

Suose

a high schl

juniors in

prefecture A...

English Test results of a high schl

juniors in prefecture A

Ha-ha-ha!

We're just

geing

started.

Histogram of "English test results"

(Range of cla = 10)

take an english

test.

Wow, you

are we

prepared

today.

This is a histogram

of that table...the

y-axis shows the

percentage of the

students in a cla

who receive that

score.

It is so much

easier to

understand

when tables are

redrawn into

histograms.

It's more

visual, you

know.

Gue what haens

when the range

of cla in this

histogram is made

smaer.

What?

Like

this...

mean

Student

standard deviation

Let's Obtain the Probability 83

Score

1

2

...

10,421

42

91

...

50

53

10

Wow! It eventuay

becomes a curved

line!

range of cla = 5

range of cla = 3

curve

range of cla = 10

Range of Cla and Histogram of

"english Test Results"

84 Chapter 5

When the range of

cla in a histogram is

decreased to the limit

at zero,

We ca the formula of that

line the probability density

function.

Theoreticay,

probability density function

there are many

types of probability

density function

graphs.

Today I wi

introduce you to

some of the most

important ones.

Please go

ahead.

Let's Obtain the Probability 85

Push