Quantitative Research Methods - central tendency and variability

Central Tendency

How do you measure it?

• The mode
• The median
• The mean

n=number of scores/participants

Measures of central tendency - numerical values referring to the centre of a distribution

Mode:

• The mode is the most frequent occurimg score
• Not commonly reported
• If two adjacent scores have the same highest frequency: report the average of the two values as the mode
• If distribution bimodal: don't report mode as a measure of central tendency

Median:

• Point at or below which 50% of the scores fall, if the scores are arranged in numerical order
• If total number of scores is odd: median is score of individual number (n+1)/2
• If total number of scores is even: median is average of scores for individual number N/2 and (N/2) +1

Mean:

• Sum of score divided by number of scores
• Most commonly reported
• Most appropriate for normal data

Mode, median and mean are identical only when distribution is symmetric and unimodal

Mode - Advantages

• Probability that randomly drawn score equals mode is higher that…