measures of dispersion

Question 1

standard deviation

Answer 1

indicates the degree of clustering of each data values about the mean adding a fairer picture of the data set that the mean, mode, median don’t

Question 2

how to calculate standard deviation

Answer 2

1. first calculate the mean
2. then place numbers in set into the formula replacing x and the mean replacing x with a line on top
3. calculate
4. all squared values add up
5. divide value by n-1
6. square root answer
7. answer = your standard deviation

Question 3

range

Answer 3

the largest value minus the smallest value
used in temperature calculations
only represents the extreme values

Question 4

interquartile range

Answer 4

difference between the 25th and 75th percentiles
method: do the process of the median from there repeat the process on the lower numbers and higher numbers to achieve UQ and LQ

Question 5

benefits of measures of dispersion to geographical understanding compared to measures of tendency

Answer 5

• allows one to establish whether the data sets are reliable and if the conclusions are representative
• used to measure confidence in statistical conclusions aiding a rejection or acceptance of a hypothesis