Computers
Using Excel for Statistical Analysis - Terms You Should Understand Before You Start by Stephen Nelson
(Contd. from page 1...)
Unless otherwise stated, the Excel functions make a critical assumption regarding the process used to select the sample: they assume that the sample drawn was drawn at random, so in this case, every household would have the same likelihood (probability) of being selected.
Tip: When making statements about a population, it is wise to verify the selection process used to form the sample. For example, if the sample were formed by randomly selecting entries from a phone book, this is not random selection of the sample-it excludes households with unlisted numbers or no telephones and includes households with multiple telephone book entries multiple times. The households don't have the same probability of being selected.
Elements versus Variables
When describing the data in a set, each member of the set is called an element. So if you're describing customers, each customer is an element. The characteristics of interest in the elements are called variables. So if you're looking at annual income, age, and sales, these would be your variables.
The experimenter manipulates the independent variable and measures the dependent variable after the manipulation to see whether it experienced any effects. A random variable describes the outcome of an experiment numerically. It can take on different values or ranges with certain probabilities. The collective group of measurements obtained for an element is called an observation.