Franklin D. Roosevelt: Life Before the Presidency. Franklin D. Roosevelt: Life Before the Presidency. Franklin Delano Roosevelt was born to James and Sara Roosevelt in 1882. James was a land-owner and businessmen of considerable, but not awesome, wealth from New York.
How to Measure Variability in Statistics. Statisticians use summary measures to describe the amount of variability or spread in a set of data. The most common measures of variability are the range, the interquartile range (IQR), variance, and standard deviation.
A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled. The independent variable is the one that is changed by the scientist. To ensure a fair test, a good experiment has only one independent variable. As the scientist changes the independent variable, he or she observes what happens. The scientist focuses his or her observations on the dependent variable to see how it responds to the change made to the independent variable.