1. Descriptive Statistics: Practical 1
Measures of Spread
Measures of Spread
The most frequently used measure for the spread is the standard deviation (or it's square: the variance). In R the commands to calculate these statistics are sd() and var(). You can use these functions the same way as the functions for central tendency.
Use the gapminder data:
What is the variance of the variable 'gdpPercap' for 1987?
What is the variance of the variable 'gdpPercap' for 1987?
The variance of the variable 'gdpPercap' for 1987#=# #68695607#
First, create a subset with only data of 1987:
Alternatively, you can do this also in one line by selecting all the rows in which the year is 1987 and selecting the column 'gdpPercap'. Apply
First, create a subset with only data of 1987:
G1987 <- G[G$year == 1987,]Then apply the function for variance on the variable gdpPercap.
var(G1987$gdpPercap)
Alternatively, you can do this also in one line by selecting all the rows in which the year is 1987 and selecting the column 'gdpPercap'. Apply
var() to this selection. var(G[G$year == 1987, 'gdpPercap'])
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