Stats Honors Test 1 (study guide)

Which are possible dangers of nonresponse?

1. Those who feel strongly about the subject are more likely to respond. 2. Those who do not feel strongly about the subject are less likely to respond.

Explain why a census is often not the best way to obtain information about a population.

A census is often not the best way to obtain information about a population because it may be difficult to enumerate all units of the population in the available time and it can take a long time to collect, process, and release data.

Explain why a sample of 25 accountants from a large city take taken to estimate the median income of all residents of that large city is not representative.

It does not reflect as closely as possible to the relevant characteristics of the population under consideration.

Observational study or designed experiment? A poll is conducted in which 292 nurses are asked about how often they accessed the internet during the past week.

Observational study

In a designed experiment, what are the experimental units?

The individuals or items on which the experiment is performed.

In a designed experiment, there is one factor with four levels. How many treatments are there?

There are four treatments.

Systematic random sampling is easier to execute than simple random sampling and usually provides comparable results. The exception is the presence of some kind of (a)_________________ (b)________________ in the listing of the members of the population.

A. Cyclical B. Pattern

Identify two forms of simple random sampling and explain the difference between the two.

Two forms of simple random sampling are simple random sampling with and without replacement. The difference between the two is that SRS with replacement allows a member of a population to be selected more than once, whereas SRS without replacement only allows a member of a population to be selected, at most, once.

Identify two methods for obtaining a simple random sample.

Two methods for obtaining a simple random sample are by using simple random sampling with replacement whereby a member of a population can be selected more than once. You can also use simple random sampling without replacement whereby a member of a population can be selected, at most, once.

Define population.

A population is a collection of all individuals or items in a statistical study. "Everyone"

Define sample.

A sample is a part of the population from which information is obtained.

What is a simple random sample?

A simple random sample is a sample that is obtained through simple random sampling.

Observational studies can reveal only association, whereas designed experiments can help establish

Causation

Designed experiment

In a designed experiment, researchers impose treatments and controls and then observe characteristics and take measurements.

Observational study

In an observational study, researchers simply observe characteristics and take measurements, as in a sample survey.

The acronym _______________ is used for simple random sampling without replacement.

SRS

What is simple random sampling?

Simple random sampling is a sampling procedure for which each possible sample of a given size is equally likely to be the one obtained.

If the experimental units are humans, what term is often used in place of experimental unit?

Subject

Why is obtaining a representative sample important?

The sample must be representative in order to use inferential statistics to draw conclusions about the entire population.

Which is a consequence of such low response rates?

The samples are not likely to be representative of their respective populations.