Graphical Representation, Measures of Central Tendency and Measures of Dispersion explained!
What is Statistics?
Statistics is a branch of Mathematics dealing with the collection, organisation ,representation and interpretation of data.
This course deals with the graphical representation of data, measures of Central tendency: Mean ,Median and Mode and Measures of Dispersion : Mean Deviation and Standard Deviation.
Statistical data can be easily understood if we represent it in the form of diagrams and graphs. Here, we study the following types of graphs: Pie Charts, Bar graphs, Histograms, Frequency Polygons. You will learn how to draw these graphs and interpret them. These form an integral part of quantitative aptitude tests.
You will learn how to draw a Pie Chart.
Given a pie chart you will answer questions based on it.
How to draw a bar graph to represent data is shown . You are taught how to interpret the data.
You are shown how to draw a Histogram and Frequency Polygon.
Statistical data has the tendency to cluster around a central value. This is called Central tendency. The different ways of measuring Central tendency are Mean, Median and Mode. You will learn how to calculate these for grouped and ungrouped data, Problems of the type given below are discussed:
Find the mean of 11,19,7,13,18,21,9,5,20,17,16,21. If the mean is reduced by 2, find the new mean.
The mean of 40 students is calculated as 18.2. One student's marks was incorrectly written as 21 instead of 29. Find the correct mean.
If 10 numbers have mean 13 and 15 numbers have mean 18, find the mean of the 25 numbers.
Find the mean for a frequency distribution having class intervals using the Shortcut Method.
You are introduced to Quartiles and how to calculate them using the formula. A few of the problems include:
Find the median 0f 10,75,3,81,17,27,24,48,12,47,9,15
The percentage of marks obtained by 100 students is given in a frequency table. Find the median.
Find the upper and lower quartiles for a given data.
How to calculate the mode for a given data.
In order to interpret the data, you should know how data is spread around a central value. This leads to measures of dispersion, namely mean deviation and standard deviation.
You will learn about Mean Deviation about the mean and mean deviation about the median for discrete and continuous frequency distributions. You move on to learning variance and standard deviation. Three methods of calculating the standard deviation are discussed. Some of the problems here are:
Calculate the mean deviation about the mean for 1,3,7,9,10,12
Calculate the mean deviation about the median for a frequency distribution.
Find the standard deviation of 3,6,11,12,18
Find the mean and standard deviation for a given set of data.
Join me in my next course on calculating moments, skewness, Correlation !
Thank you . I hope this course helps you!