There are three measures of central tendency: the mean, the median, and the mode. Measures of dispersion include the range, the standard deviation, and the variance (where the measure of central tendency is the mean), and the interquartile range (where the measure of central tendency is the median). Describe these measures and explain which of these measures you would use to provide an overview of

(a) nominal,

(b) ordinal and

(c) interval data?