Statistics

Which is most accurate?

A parameter is a constant although its value may be unknown.

The variance of XX, which is equal to σ2/n, is

smaller than the variance σ2 of individual observations.

_____ sampling is preferred when the objective is to increase precision.

stratified

A ______ captures a small number of people who fit a particular category.

survey

Which of the following is an example of a sample statistic?

x̄ (sample) mean

Which of the following is an example of a population parameter?

μ (population) mean

The standard deviation of P equals

√p(1−p)n

A sample statistic is considered biased if

it systematically over- or under-estimates the unknown parameter being estimated.

As a general guideline, the normal distribution approximation can be used to describe the sampling distribution of the sample mean when

n ≥ 30.

We use a sample statistic to make inferences about an unknown population _____.

parameter

When interpreting the covariance between variables x and y, which of the following statements is the most accurate?

A positive value of covariance indicates that, on average, if x is above its mean, then y tends to be above its mean.

One way to battle social-desirability bias is to use ______ surveys.

online

Cluster sampling works best

when most of the variation in a population is within groups and not between groups.

When the finite population correction factor is applied to the sample mean, the resulting standard error for the sample mean is equal to

√(p(1-p)/n) times √((N-n)/(N-1))

A population consists of all items of interest in a statistical problem, whereas a ______ is a subset of the population.

sample

_______-________ bias occurs when voters provide incorrect answers to a survey or poll because they think that others will look unfavorably on their ultimate choices.

social-desirability

For an X chart, control limits are calculated as

μ ± 3σ√n

_________ involves dividing a population into mutually exclusive and exhaustive groups, called clusters, and then selecting a random sample from these clusters for analysis.

Cluster sampling

What is a primary requirement of a "good" sample?

It is representative of the population we are trying to describe.

The branch of statistics that uses sample statistics to estimate a population parameter or test a hypothesis about such a parameter is BEST referred to as ______ statistics.

inferential

If a sample statistic consistently over- or under-estimates a population parameter, then there is _______.

bias

When the information from a sample is not typical of information in the population in a systematic way, we say that ______ has occurred.

bias

A ____ is representative of population data.

census

Nonresponse bias occurs when

those responding to a survey or poll differ systematically from the non-respondents.