ISDS CH. 7 Questions

Estimate

A particular value of an estimator

A subset of the population

A sample is

Bias

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

Statistic

Random Variable

0.25

Random samples of size 400 are taken from a population whose population proportion is 0.25. The expected value of the sample proportion is ________.

Inferential Statistics

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 ______________.

Approaches a normal distribution

The central limit theorem states that as n gets larger, the sampling distribution of the sample proportion

Proportion of successes in the population

The expected value of P^- is the

u~

The expected value of X^- is equal to _____.

u~

The expected value of the sample mean

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

Nonresponse bias occurs when

(o^2)/n

The variance of the sample mean

Sample

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

Representative of the population from which it was chosen

A simple random sample is a sample of observations that is

Central Limit Theorem

A theorem that allows us to use the normal probability distribution to approximate the sampling distribution of the sample mean whenever the sample size is large is known as the

n >_ 30

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

Parameter

Constant

Normal

If the shape of the population from which a simple random sample is drawn is normal, then the shape of the sampling distribution of X^- is

Stratified Random Sampling

In __________, the population is divided up into mutually exclusive and collective exhaustive groups called strata. The sample consists of randomly-selected elements from each stratum.

To increase precision

Stratified sampling is preferred to cluster sampling when the objective is

0.625 10/ (square root of 256) = 0.625

The population has a mean of 50 and a standard deviation of 10. A random sample of 256 is selected. The standard error of X^- is equal to ________.

(o~)/ (square root of n)

The standard deviation of the sample mean

Estimator

When a sample statistic is used to make inferences about a population parameter, it is referred to as a

The sample is not representative of the population we are trying to describe.

Which of these is a characteristic of a "bad" sample?

Sampling distribution of X^-

The probability distribution of the sample mean is commonly referred to as the _____________.