Psychology 2810 Chapter Notes - Chapter 2: Standard Deviation, Percentile, Frequency Distribution

• School: Western University
• Department: Psychology
• Course: Psychology 2810
• Professor: Stephen Lupker

Document Summary

Data set- refers to a sample or a population. Numerical descriptive measure- tools for samples to make inferences about the corresponding measures for a population. Central tendency: measures of central tendency- nd the centre value for a given statistic of a sample, mean. The sum of the measurements, divided by the number of measurements contained in the data set, for a set of quantitative data. Denoted by x-bar: x (for a given sample) I=1, go up to n, xi = (x1 + x2 + x3 + x4 ++ xn) The accuracy of an inference of population mean based on sample mean depends on two factors: 1. The sample size- the larger the sample, the more accurate the estimate tends to be: 2. The variability, or spread, of the data- all other factors remaining constant, the more variable the data (ie. not consistent), the less accurate the estimate: median.