Sections:
3-1 to 3-2: Measures of center

Introduction
What we have done so far:

Introduction
What we have done so far:
I
we have discussed various methods of collecting
sample
data.

Introduction
What we have done so far:
I
we have discussed various methods of collecting
sample
data.
I
we then learned to summarize the sample data using
frequency distribution; we also visualized the data using
histogram and other graphs.

Introduction
What we have done so far:
I
we have discussed various methods of collecting
sample
data.
I
we then learned to summarize the sample data using
frequency distribution; we also visualized the data using
histogram and other graphs.
In the next two lectures, we will talk about ideas to describe the
“
center
” and the “
spread
” or the “
variation
” of the data. We
will also discuss other related ideas.

Measure of the center: Mean
The measure of the center of the data is
a value at the center
or
the
middle
of the data set.

Measure of the center: Mean
The measure of the center of the data is
a value at the center
or
the
middle
of the data set.
We will talk about two notions of the center of the data, namely
the
mean
and the
median
.

Measure of the center: Mean
The measure of the center of the data is
a value at the center
or
the
middle
of the data set.
We will talk about two notions of the center of the data, namely
the
mean
and the
median
.
Mean
or
Average
:
this is a measure of the center of the data set,
which is obtained by adding all the data values and then dividing
by the number of data values in the set.

Measure of the center: Mean
The measure of the center of the data is
a value at the center
or
the
middle
of the data set.
We will talk about two notions of the center of the data, namely
the
mean
and the
median
.
Mean
or
Average
:
this is a measure of the center of the data set,
which is obtained by adding all the data values and then dividing
by the number of data values in the set.
The
mean
of the data is also called the
Arithmetic mean
.

Measure of the center: Mean
Notations:
P
denotes the sum of a set of values: pronounced
sigma

Measure of the center: Mean
Notations:
P
denotes the sum of a set of values: pronounced
sigma
x
is a variable usually used to to represent
the individual data values

Measure of the center: Mean
Notations:
P
denotes the sum of a set of values: pronounced
sigma
x
is a variable usually used to to represent
the individual data values
n
represents the number of data values in a
sample

Measure of the center: Mean
Notations:
P
denotes the sum of a set of values: pronounced
sigma
x
is a variable usually used to to represent
the individual data values
n
represents the number of data values in a
sample
N
represents the number of data values in a
population