chapter 4

A simple random sample of size n is chosen in a way that every group of n individuals in the population has an equal chance to be selected in the sample.

An item or individual can only be selected once

An item or individual can be selected more than once

Groups of individuals in a population that share characteristics thought to be associated with the variables being measured in a study

A sample selected by choosing an SRS from each stratum and combining the SRSs into one overall group

Groups of items and individuals in the population that are located near each other

A sample selected by choosing an SRS of clusters and including each member of the selected cluster in the sample

A sample selected from an ordered arrangement of the population by randomly selecting the first k items or individuals in the pop. and choosing every kth item or individual thereafter

Consists of members of the pop. that are easy to reach

The design of a statistical study shows bias if the resulting sample statistics is very likely to underestimate or very likely to overestimate the population parameter due to a flaw in the data collection process

Consists of people who choose to be in the sample by responding to a general invitation

Some members of a population are less likely to be chosen or not chosen at all in the sample

An individual chosen for the sample cannot be contacted or refuses to participate

A response to a survey question consistently differ from the truth in the same way

Delibarately exposes treatments on experimental units to measure their responses

Measures the outcome of a statistical study

May help explain or predict changes in a response variable

Explanatory vars that are manipulated and may cause a change in the response variable

Different values of a factor

A specific condition applied to the items or individuals in an experiment

The item or individual to which the treatment is assigned

Experimental unit is human

Observes items or individuals and measures variables of interest, but doesn't impose treatments

When the observational units are selected at a point in time and data about them are gathered from the past

When the observational units are selected at a point in time and data about them are gathered both at that time and in the future

An observational study in which data is collected from people by asking them a common set of questions

Variables other than the explanatory var that may have an effect on the response variable in a statistical study

An extraneous variable that is associated with both the explanatory var and the response var in a statistical study; makes it difficult to determine whether the changes in the explanatory var are changes in the response var

Used to provide a baseline for comparing the effects of other treatments.

A treatment w/ no active ingredient but is otherwise like other treatment

Some subjects in the experiment will respond favorably to any treatment, even an inactive one

Means that treatments are assigned to experimental units (or experimental units are assigned to treatments) using chance process

The experimental units are assigned to the treatments completely at random

Being able to do the study more than once, more so to validate the results of the study

Keeping the value of some extraneous variables the same for all experimental units

A group of experimental units that are known before the experiment to be similar in some way that's expected to affect the response to the treatments

Var used to form blocks

Random assignment of experimental units to treatments is carried out separately within each block so that all treatments occur in each block

Experiment design for comparing two treatments that use blocks of size 2.

When an observed difference in response between two groups of an experiment is so large that it's unlikely to be explained by chance variation

The distribution of a statistic generated by repeatedly reassigning the response values to treatment groups.