Exam 2

we calculate a parameter to make inferences about a statistic

false

a paramater is a random variable, whereas a sample statistic is a constant.

false

selection bias occurs when the sample is mistakenly divided into strata and random samples are drawn from each stratum

false

a simple random sample is a sample of "n" observations which has the same probability of being selected from the population as any other sample of "n" observations

true

if we had access to data that encompasses the entire population, then the value of the paramaters would be known and no statistical interference would be needed.

true

in stratified random sampling, the population is divided into mutually exclusive and collectively exhaustive groups, called strata. a stratified sample includes randomly selected observations form each stratum, which are proportional to the stratums size.

true

nonresponse bias occurs when those responding to a survey or poll differ systematically from the non-respondents

true

when a statistic is used to estimate a parameter, the statistic is refereed to as an estimator. a particular value of the estimator is called an estimate

true

bias refers to the tendency of a sample statistic to systematically over or underestimate a population parameter

true

a sample consists of all items of interest in a statistical problem, whereas a population is a subset of the population. we calculate a parameter to make inferences about the unknown sample statistic.

false

a population consists of all items of interest in a statistical problem

true