Standard Deviation

Question 1

Standard deviation

Answer 1

Much more sophisticated measure of dispersion. Single value that tells us how far scores deviate (Move away from)the mean. The larger the standard deviation, the greater the dispersion or spread within a set of data

Much more precise measure of dispersion than range as it includes all values within the final calculation. However for this reason it can be distorted by a single extreme value. Also extreme values may not be revealed.

Question 2

Eval of mean

Answer 2

Most sensitive- includes all scores in the data set- more representative

Easily distorted by extreme values

Question 3

Eval of median

Answer 3

Extreme scores do not affect it, easy to calculate

Less sensitive than mean as actual values of lower and higher numbers are ignored, extreme values may be important.

Question 4

Eval of mode

Answer 4

Easy to calculate, crude measure. Doesn’t represent whole data set. Might be several modes-not useful.

For some data mode might be only method you can use. For example asking group favourite footballer.

Question 5

Eval of range

Answer 5

Easy to calculate, only takes into account two most extreme values. May be unrepresentative of whole set.

Range doesn’t indicate whether most numbers are closely groups around the mean or spread out. -standard deviation does.