Terms to know quantitative variable valid percent normal curve histogram skewness positive and negative skewness outlier mode, median, mean bimodal distribution variance, range, standard deviation, inter-quartile range percentile. Ratio (quantitative) variables: counts, could be the total amount of students in the class, amounts, university classes, the amount could be the total cost of the text for each class. Frequency distributions for quantitative variables are not so useful, they end up. Frequency distributions for rat vars with huge tables, which make it hard to find median and mode. Valid is on the total number of cases that actually answered. Percent is on the total cases including the missed ones. Reminder: note the difference between percent and valid percent . When we have quantitative variables we don"t use frequency tables, they are too long. We are concerned with the shape of the distribution, shape matters because it effects what we do with the data.