# AP Statistics Chp.5

#### Study  only

Flashcards Flashcards

Scatter Scatter

Scatter Scatter

## Create a new folder

### bias

the design of a statistical study shows bias if it systematically favors certain outcomes

### Block

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

### census

a study that attempts to collect data from every individual in the population

### Cluster sample

divide the population into smaller groups. These clusters should mirror the characteristics of the population. Then choose an SRS of the clusters. All individuals in the chosen clusters are included in the sample.

### Completely randomized design

when the treatments are assigned to all the experimental units completely by chance

### confounding

two variables are associated in such a way that their effects on a response variable can't be distinguished from each other.

### control

controlling for as many lurking vars as possible, by using a comparative design and making sure the only difference between the groups is the treatment administered.

### Control group

a experimental group that serves as a baseline for comparing the effects of other treatments. may be a placebo, commonly used to measure the difference between psychological and physical effects.

### convenience sample

a sample selected by taking the members of the population

### double-blind

an experiment in which neither the subject nor the administrator that measures the response variable know which treatment a subject received

### experiment

deliberately imposes some treatment on individuals to measure their responses

### experimental units

person, a plot of land, a machine, etc. that forms the 'material' on which an experiment is performed.

### explanatory variables

a variable that helps explain or influences changes in a response variable

### factor

the explanatory variables in an experiment

### level

specific value of an explanatory variable(factor) in an experiment

### lurking variable

a variable that is not among the explanatory or response variables in a study but that may influence the response variable.

### matched pair

a form of blocking for comparing just two treatments. In some, each subject receives both treatments in a random order. In others, the subjects are matched in pairs as closely as possible, and each subject in a pair is randomly assigned to receive one of the treatments

### non response

when a selected individual can't be contacted or refuses to cooperate, example of a nonsampling error

### observational study

observes individuals and measures variables of interest but does not attempt to influence the responses

### placebo

an inactive (fake) treatment

### placebo effect

describes the fact some subjects respond favorably to any treatment(psychological effect)

### population

entire group of individuals from which we want information

### random assignment

assign experimental units to treatments by chance

### random sampling

use of chance to select a sample

### randomized block design

forming blocks consisting of similar individuals. random assignment of treatments

### replication

use enough experimental units in each group so that any differences in the effects of the treatments

### response bias

a systematic pattern of incorrect responses

### response variable

a variable that measures an outcome of a study

### sample

the part of the population from which we collect information. we use information from a sample to draw conclusions about an entire population

### sampling error

mistakes while taking a sample, that lead to inaccurate information about a population

### SRS(simple random sample)

gives every possible sample the same chance to be chosen.

### stratified random sample

classify the population into similar individuals , then get an SRS from each strata

### subjects

experimental units that are human beings

### treatment

specific condition applied to individuals in an experiment

### undercoverage

occurs when some members of the population are left out of the sampling; a type of sampling error

### voluntary response samples

people decide whether to join a sample; biased by people with strong opinions

Example:

## Press Ctrl-0 to reset your zoom

### It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

For more help, see our troubleshooting page.

Create Set