INTRO TO STATS EXAM SLCC
QUESTIONS AND ANSWERS
Coefficent of Variation (CV) - Answer-Ratio of the standard deviation to the mean of
data set
Std. dev / mean
Higher CV = more spread
When converting units of measure, the CV is unchanged
Statcrunch = coef of var (displayed as percentage, don't forget to divide by 100)
Empirical Rule - Answer-For bell-curve data
68% of data within 1 std dev
95% within 2 std dev
99.7% within 3 std dev
sample standard deviation - Answer-s
Statcrunch = std dev
population standard deviation - Answer-σ (sigma)
Statcrunch = unadj. std. dev
Random sampling - Answer-a sample that fairly represents a population because each
member has an equal chance of inclusion
ex: pull #'s out of hat
Systematic sampling - Answer-randomly select some starting point and then select
every kth element in the population
ex: 5th customer to come out of store and then every 7th after that.
stratified sampling - Answer-A type of probability sampling in which the population is
divided into groups with a common attribute and a random sample is chosen within
each group
homogeneous, non-overlapping strata
Ex: freshmen, soph, juniors and seniors could be strata
QUESTIONS AND ANSWERS
Coefficent of Variation (CV) - Answer-Ratio of the standard deviation to the mean of
data set
Std. dev / mean
Higher CV = more spread
When converting units of measure, the CV is unchanged
Statcrunch = coef of var (displayed as percentage, don't forget to divide by 100)
Empirical Rule - Answer-For bell-curve data
68% of data within 1 std dev
95% within 2 std dev
99.7% within 3 std dev
sample standard deviation - Answer-s
Statcrunch = std dev
population standard deviation - Answer-σ (sigma)
Statcrunch = unadj. std. dev
Random sampling - Answer-a sample that fairly represents a population because each
member has an equal chance of inclusion
ex: pull #'s out of hat
Systematic sampling - Answer-randomly select some starting point and then select
every kth element in the population
ex: 5th customer to come out of store and then every 7th after that.
stratified sampling - Answer-A type of probability sampling in which the population is
divided into groups with a common attribute and a random sample is chosen within
each group
homogeneous, non-overlapping strata
Ex: freshmen, soph, juniors and seniors could be strata
