We did a quiz and went revised what standard deviation is.
Standard deviation (σ is the symbol, is a measure of the variance from the mean for a set of data. It is calculated as follows:
x̄ (pronounced as x bar) is the mean of the data set.
n is the number of data in the set.
Σ, or summation, is the addition of all the following datum. In this case, it is (x-x̄)^2.
Showing the proper working during the examples is essential to getting the method mark(s).
Calculate the mean, median and standard deviation for the following set of data.
mean = (1+2+3)/3
Tmedian = (3+1)/2
median = 2
standard deviation = √( ( (1-2)^2 + (2-2)^2 + (3-2)^2 ) / 2 )
The standard deviation’s and mean’s working can be in the form of a table containing all the data, and you can just use the values of Σ(x-x̄), n and Σx to calculate your answers.
If there are UNITS in the question, be sure to write them down in your answers as well.
- Write scale when drawing graphs
- Show ALL the working when calculating the standard deviation, mean and median.
Check out these G+ posts to learn how to use STAT functions in your calculator
p.s. Sorry for the late post!