STAT 100 Lecture Notes - Lecture 5: Squared Deviations From The Mean, Interquartile Range, Summary Statistics

• School: University of Maryland
• Department: Statistics and Probability
• Course: STAT 100
• Professor: Cremins

Document Summary

Descriptive measures of populations are called parameters. Parameters are often written using greek letters ( ). We know only part of the entire data. Descriptive measures of samples are called statistics. Statistics are often written using roman letters (x) Center of the data: numeric values that represent the average or typical value of a quantitative variable. Variation or measures of dispersion: numeric values that represent the degree to which the values are spread out. The mean (arithmetic mean) of a variable is often what people mean by the average add up all the values and divide by the number of measurements in the data set. To compute the arithmetic mean of: 6, 1, 5. Add up the three numbers and divide by 3: (6+1+5)/3 = 4. 0. The arithmetic mean is 4. 0, one more decimal place than the data. One interpretation: the arithmetic mean can be thought of as the center of gravity, where the yardstick balances.