# USP493 Session 2 Notes

## Introduction to Simple Univariate Descriptive Statistics

1. Frequencies and Percentage Distributions
1. Can be used for nominal and ordinal variables, interval usually when the data are collapsed.
2. Difference between proportions (f/N) and percentages (f/N)* 100
3. How to set up
1. Put the values of the variable along the side, including totals, list frequencies or percentages in a second column
2. But what if you have interval data?
1. One way to group the data
1. Subtract the lowest value from the highest value
2. Divide the subtraction by 10, this will give you your approximate class interval (ie how large each group is)
3. Round what you found in “b” so it is either an even number or a multiple of 5.
4. Establish the smallest interval so it starts with a multiple of the number you calculated in “c”
5. Group the data into these ranges
3. And what do you do with missing values?
1. If important, percentage them
2. Otherwise list in the bottom of the table