A PLEASANT MORNING
TO EVERYONE !!!

LET US BE UNITED
Form a figure out of the pieces of
the puzzle provided.
(2 mins.)

QUESTIONS:
•What have you formed? Say something about
the figure.
•Is there similar graphs?

•If we are to group the graphs/figures you formed,
which should be together?
•How do these figures differ from each other?

OBJECTIVES:
•Determine / enumerate the characteristics of
a normal distribution.
•Sketch / construct a normal curve which
represents a normal distribution.
•Cite real-life examples involving normal
distribution.

Normal Distribution
If a distribution consists of a very large number of
cases and the three measures of averages (mean,
median, mode) are equal, then the distribution is
symmetrical and the skewness is 0. In Statistics,
such distribution is called normal distribution or
simply normal curve.

The normal curve has a very important
role in inferential statistics. It provides a
graphical representation of statistical
values that are needed in describing the
characteristics of populations as well as
in making decisions. It is defined by an
equation that uses the populations
mean, and the standard deviation. There
is no single curve, but rather a whole
family of normal curves have the same

The normal probability distribution has
the following properties:
1. The distribution curve is bell-shaped.

2. The curve is symmetrical about its center.
3. The mean, the median, and the mode
coincide at the center.
4. The width of the curve is determined by
the standard deviation of the distribution.

5. The tails of the curve flatten out indefinitely
along the horizontal axis, always approaching the
axis but never touching it. That is, the curve is
asymptotic to the base line.
6. The area under the curve is 1. Thus, it
represents the probability or proportion or the
percentage associated with specific sets of
measurement values.

APPLICATION:
Cite some examples in real-life
where you can see the normal curve
or distribution.

Student’s Average Report

Shoe Size

Birth Weight

Income Distribution in Economy

Technical Stock Market

GENERALIZATION:
What are the properties of the normal
distribution?

EVALUATION:
Modified True or False
If the statement is true or check, write the letter T, but if the statement is wrong
then change the underlined word to make the statement right.
1. The standard normal distribution is also called normal
curve.
2. The area under a normal curve is 100.

3. The mean of a standard normal curve is 3.
4. The curve of a normal distribution extends
indefinitely at the tails.
5. The shape of the normal probability distribution is
symmetric about the mean.

AGREEMENT
Study about the lesson.