Statistics Sampling methods MAT 104

a survey of an entire population is called a

census

categorical (qualitative ) data

pieces of information that allow us to classify the objects under investigation into various categories

Quota sampling

is a variation on stratified sampling, wherein samples are collected in each subgroup until the desired quota is met

cluster sampling

the population is divided into subgroups (clusters), and a set of subgroups are selected to be in the sample

systematic sampling

every nth member of the population is selected to be in the sample

Convenience sampling

is samples chosen by selecting whoever is convenient.

Voluntary response sampling

is allowing the sample to volunteer

Sampling bias

when the sample is not representative of the population

Voluntary response bias

the sampling bias that often occurs when the sample is volunteers

Self-interest study

bias that can occur when the researchers have an interest in the outcome

Response bias

when the responder gives inaccurate responses for any reason

Perceived lack of anonymity

when the responder fears giving an honest answer might negatively affect them

Non-response bias

when people refusing to participate in the study can influence the validity of the outcome

observational study

is a study based on observations or measurements

experiment

is a study in which the effects of a treatment are measured

placebo effect

is when the effectiveness of a treatment is influenced by the patient's perception of how effective they think the treatment will be, so a result might be seen even if the treatment is ineffectual

blind study

is one in which the participant does not know whether or not they are receiving the treatment or a placebo.

double-blind study

is one in which those interacting with the participants don't know who is in the treatment group and who is in the control group.

Loaded questions/leading questions

when the question wording influences the responses

Question order

where the order of questions changes the results.

confounding

occurs when there are two potential variables that could have caused the outcome and it is not possible to determine which actually caused the result

control group

the ______ ______ does not receive the treatment.

treatment group

The _________ _________ receives the treatment being tested

population

of a study is the group the collected data is intended to describe.

of a study is the group the collected data is intended to describe.

are responses that are numerical in nature and with which we can perform meaningful arithmetic calculations.

Sampling bias

A sampling method is biased if every member of the population doesn't have equal likelihood of being in the sample.

Simple random sample

A random sample is one in which each member of the population has an equal probability of being chosen. A ___________________ is one in which every member of the population and any group of members has an equal probability of being chosen.

Sampling variability

The natural variation of samples is called sampling variability. This is unavoidable and expected in random sampling, and in most cases is not an issue.

Stratified sampling

a population is divided into a number of subgroups (or strata).Random samples are then taken from each subgroup with sample sizes proportional to the size of the subgroup in the population

Parameter

is a value (average, percentage, etc.) calculated using all the data from a population

Sample

is a smaller subset of the entire population, ideally one that is fairly representative of the whole population

Statistics

A _______ is a value (average, percentage, etc.) calculated using the data from a sample.