January 4, 2008

by shreeradha •
Uncategorized
• Tags: Stats And Maths

(This blog does not support formatting therefore sometimes there could be errors in the post.)

Dispersion

Dispersion gives idea of spread of data from the central value say mean.

Deviation.

Deviation is the difference between a observation and some reference value. Observation value is usually represented by X bar.

Deviation of x from some value A is X — A.

Deviation from mean is X – X

Absolute deviation

When deviation is always taken as positive irrespective of its sign, it is called as absolute deviation. It is represented as | X – X |

Mean deviation

It is sum of absolute deviations from mean divided by total number of observations. See chapter 2 for examples.

Standard Deviation

It is square root of sum of squares of mean deviation divided by total number of observations. See chapter 2 for examples.

Variance

Variance is square of standard deviation. See chapter 2 for examples.

Quartile deviation

It is the difference between the third quartile and first quartile divided by 2. It is also called as semi quartile range. See chapter 2 for examples.

Inter Quartile range

It is the difference between the third quartile and first quartile. See chapter 2 for examples.

Range

Range is the difference between the largest value and the smallest value of the data set. See chapter 2 for examples.

January 4, 2008

## stats 11

^{0}by shreeradha • Uncategorized • Tags: Stats And Maths

(This blog does not support formatting therefore sometimes there could be errors in the post.)

Dispersion

Dispersion gives idea of spread of data from the central value say mean.

Deviation.

Deviation is the difference between a observation and some reference value. Observation value is usually represented by X bar.

Deviation of x from some value A is X — A.

Deviation from mean is X – X

Absolute deviation

When deviation is always taken as positive irrespective of its sign, it is called as absolute deviation. It is represented as | X – X |

Mean deviation

It is sum of absolute deviations from mean divided by total number of observations. See chapter 2 for examples.

Standard Deviation

It is square root of sum of squares of mean deviation divided by total number of observations. See chapter 2 for examples.

Variance

Variance is square of standard deviation. See chapter 2 for examples.

Quartile deviation

It is the difference between the third quartile and first quartile divided by 2. It is also called as semi quartile range. See chapter 2 for examples.

Inter Quartile range

It is the difference between the third quartile and first quartile. See chapter 2 for examples.

Range

Range is the difference between the largest value and the smallest value of the data set. See chapter 2 for examples.