Showing posts with label Measure of Dispersion. Show all posts
Showing posts with label Measure of Dispersion. Show all posts

Wednesday, October 17, 2018

Python for Data Science - Basics, Descriptive Statistics, Hypothesis Tes...







This video focuses on Basics of Python for Data Science. Descriptive Statistics including Measures of Central Tendency, Dispersion, Asymmetry and Relationship. Hypothesis Test covered are 2 Sample Independent Ttest, Anova Single Factor, Chi Square Test of Independence. The video also covers Label Encoding, splitting the data frames. Regression models like Multiple Linear Regression, Decision Tree and Random Forest

Sunday, September 14, 2014

STANDARD DEVIATION - Descriptive Statistics using Microsoft Excel Statistical Functions - Measure of Dispersion

The practice sheet can be downloaded from Link. Statistics Marks Data - Download Sheet

About the Data Sheet - The data in this sheet is related to marks scored by 100 Students in a Statistical Test. 

Based on the data, we will use Microsoft Excel Statistical functions to analyse the descriptive statistics. 

In the Data Sheet, we have Data from A2:A101, A1 being the header of the Data. 

STANDARD DEVIATION

Standard Deviation is measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. Standard deviation is calculated as the square root of variance.

Standard deviation is calculated based on a sample. The standard deviation is a measure of how widely values are dispersed from the average value (the mean).

= STDEV(number1,number2,...)

STDEV uses the following formula:

where x is the sample mean AVERAGE(number1,number2,…) and n is the sample size.
Or
=SQRT(Variance)

In the Data Sheet, we have Data from A2:A101, A1 being the header of the Data. 
=STDEV(A2:A101)
Result is 14.24
Or
=SQRT(Variance) or =SQRT(202.7777)

STDEV.P is for population
STDEV.S is for Sample


The practice sheet can be downloaded from Link. Statistics Marks Data - Download Sheet

VARIANCE - Descriptive Statistics using Microsoft Excel Statistical Functions - Measure of Dispersion

The practice sheet can be downloaded from Link. Statistics Marks Data - Download Sheet

About the Data Sheet - The data in this sheet is related to marks scored by 100 Students in a Statistical Test. 

Based on the data, we will use Microsoft Excel Statistical functions to analyse the descriptive statistics. 

In the Data Sheet, we have Data from A2:A101, A1 being the header of the Data. 

Variance
Variance (σ2) is a measure of the dispersion of a set of data points around their mean value.
In other words, variance is a mathematical expectation of the average squared deviations from the mean.
Variance measures the variability from an average (volatility).

=VAR(number1,[number2],...])

VAR uses the following formula:


where x is the sample mean AVERAGE(number1,number2,…) and n is the sample size.

In the Data Sheet, we have Data from A2:A101, A1 being the header of the Data. 

=VAR(A2:A101)
Result is 202.7777

VAR.P is for Population
VAR.S is for Sample.

Higher the variance the more the volatility or values are more different.
Lower the variance the lesser the volatility or values are less different.