PSY 3010-Statistics for Psychology -
Chapter 4, Exam 1
Define dispersion (Duplicate question) - ANS A term that refers to how different scores are from
each other and from the mean; can be used interchangeably with the word variability
Which measure of variability is seldom used because it ignores "clumping". - ANS The range
As sample size increases, the range __________. - ANS Gets bigger
In general, the larger the sample, the _____ the range. - ANS Larger
Give the full name and symbol for the "average squared distance that scores are to the
population mean". - ANS Variance of the population; sigma squared
The variance of a sample of raw scores is the average _______________. - ANS Squared
distance X is to Xbar
Which measure of variation expresses itself as squared units? - ANS Variance
Give the full name and symbol for the "average distance that scores are to the sample mean." -
ANS Standard deviation of the sample; S
_____________ describes the average distance that X is to xbar. - ANS Standard deviation of
the sample
What does the symbol (sigma squared) stand for? - ANS Variance of the population
Define (symbol) sigma. - ANS The average distance scores are to the mean of the population.
Which formula would you use to calculate the standard deviation of the population? See book.
Question 12, page 73. - ANS C
Of the measures of variation we've learned about, which is the most commonly used? - ANS
Standard deviation
What do each of the following symbols stand for and state whether each is calculated from the
sample or the population.
A) Sigma squared
B) S squared
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