5.
Statistics-Part 1
Mean- actually
is the average but with a difference.
The average represents a given sample of numbers.
Calculation
of Average:
Sum of all the values/ Total number of values
F5.1.1.0
The difference between the mean and average is that the average
is given by the above formula whilst the mean is the average of two or more
sets of data.
Average is also known
as arithmetic mean.
Example
5.1.1.0:
Given, 1, 1, 2, 3, 4
Mean = Sum of observation/Total number of
observations
= (1 + 1 + 2 + 3 + 4)/5
= 2.2
Mean
is used in cases where there is grouped data.
Median
This is the middle value and is calculated as follows:
If no of data is even
n/2
In case of odd:
(n/2) +1
Mode
Mode is the most common value.
Range
It gives an idea of
how spread data is.
To calculate range:
Range=Biggest value−Smallest Value
This is calculated as Hi-Lo’
Quartile
The median breaks a
set of data in two and a quartile breaks into four equal parts.
To calculate the Lower Quartile (LQ):
=n+1/4
The Upper Quartile (UQ)
=3Xn+1
Interquartile range
The Interquartile range is the difference between the Upper
Quartile (UQ)
=UQ-LQ
Scatter Diagram
A scatter diagram examines the relationship
between the x and y-axis. If points are one line then correlation is perfect
and is in unity.
What is correlation?
Ans:
In X, Y axis when y tends to increase as x increases
we say it has a positive
correlation.
+VE
1.1a Perfect Positive Correlation 1.1b Perfect Negative Correlation
In X, Y axis when y tends to decrease as x decreases we say it
has a negative correlation.
-VE
Sometimes there is no clear relationship between
X and Y, we call it No correlation.
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