X Problem 1.4 For each of the following variables, determine whether the variable is categorical or numerical and determine its measurement scale. If the variable is numerical, determine whether the variable is discrete or continuous. (Note: do not do the part of measurement scale. If the variable is categorical, determine whether the variable is nominal or ordinal). a) Number of cellphones in the household b) Monthly data usage (in MB) C) Number of text messages exchanged per month d) Voice usage per month (in minutes) e) Whether the cellphone is used for email