Understanding HCI

Performance Measurement

Examples

Find the mean, median and standard deviation of the following set of numbers:

1, 1, 2, 2, 2, 3, 3, 3, 3, 4, 5, 6, 6

mean

Add up all the numbers and divide by the number of numbers

1 + 1 + 2 + 2 + 2 + 3 + 3 + 3 + 3 + 4 + 5 + 6 + 6 = 41

35/13 = 3.154

the mean is 3.154

Median

The median is the middle value - half the scores are lower and half are higher. In 13 numbers ordered in ascending order, the 7th number is the median.

1, 1, 2, 2, 2, 3, 3, 3, 3, 4, 5, 6, 6

the median is 3

mode

The mode is the most frequently occuring number. 3, occuring 4 times, occurs most often in our set and so this is the mode.

the mode is 3