Math of Geography

Question 1

why is calculating standard deviation useful?

Answer 1

• useful in determining validity in the data set
• a number above 1 means there is a large spread of data around the mean
  > not a lot of clustering
  > many extreme values
• standard deviation is able to show the extent of fluctuations in standard deviations over time
  > able to compare data sets easily

Question 2

how do you calculate percentage change?

Answer 2

difference ( final - initial) / initial number x 100

Question 3

how do you calculate percentage decrease?

Answer 3

initial - final/ initial x 100