Question

Explain why we cannot calculate the mean and standard deviation for scores on a categorical variable.

Answer 1

Categorical variables are nominal data which can not measure numerically ( i.e not in digit).these are qualitative data .suppose there are 5 person in a group in which 3 of them smoke and 2 are not smoke. So here we can not measure in number .In this case to get a better idea about the data we usually use MODE .here mode will be measure of central tendency , as 3 of them smoke so smoke will be central tendency .

average and standard deviation are function of quantitative data.

For example . We can calculate average of marks of class.

Thanks!