SOAN 2120 Lecture Notes - Variance, Standard Deviation, Statistical Significance
Document Summary
Population parameters the entire group we are interested in. Sample statistics a portion of the population. N number of values in your data set. Measures of variability - range, deviation, variance, standard deviation. Deviation how far a measurement is form the mean/average of the set. Variance - to find sample variance sum of the squared of deviations divided by n minus 1 from the number of values in a set. Take x" substract mean and divide by standard deviation. The x is where you plug in the obersavtion number which is the number you see in the data set. The x with line over top is the mean. **note this: population and sample formula are really the same. You still plug everything in the same way. outlier just get rid of it it"s that number that"s way off from the rest of the data set. Every observation can be converted to a z-score.