Psychology Statistics Chapter 4

Variability

the degree to which scores in a distribution are spread out or clustered together

Range

the distance between the largest score and the smallest score in the distribution

Range (X) = Max - Min

range = 75 - 3

Variance

sum of squared deviations/number of scores

he average of the squared deviations from the mean

Unbiased estimate of populaion parameter

if the average value of the sample statistic done countless times, is equal to the population parameters

many sample statistic = population parameter

biased estimate of the population parameter

systematically overestimates or
underestimates the population parameter

Adding a constant to each score DOES NOT change the Standard Deviation

If you have a quiz score of 7, and your friend has a quiz score of 5, what happens to the distance between these scores if 5 points are added to every score?

Multiplying each score by a constant DOES change the Standard deviation

If you have a quiz score of 7, and your friend has a quiz score of 5, what happens to the distance between these scores if 3 points are multiplied to every score?