Friday, 13 January 2017

STATISTICS(basic concept) NOTES for RRB NTPC EXAM

Statistics
The words ‘Statistics’ appears to have been derived from the latin word ‘status’ meaning a (political) state. In its origin, Statistic was simply the collect of data on different aspects of the life of the people.
Statistics deals with data collected for specific purposes. We can make decisions about the data by analysing and interpreting it.
Central line tendency


Mean: The mean or average of a number of observation is the sum of the value of all the observation divided by the total number of the observations.
It is denoted by the symbol,  read as x bar

Here n is a number of observation.



Example- people were asked about the time in a week they spend in doing social work in their community. They said 10, 7, 13, 20 and 15 hours respectively.Find the mean (or average) time in a week devoted by them in social work.




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