Statistics

What is in columns

categories

What is in rows

individual observations

What are in lines

Cases

What is numerical continuos data

Data that has no gaps (can’t have 1/2 of a person)

What is numerical discrete data

Data that has gaps (ex. money. $34.54)

What is regular categorical data

Data that has categories with an order (ex. candy types)

What is Categorical ordinal data

Categories with an order (ratings of a movie in terms of sucks, good, great)

What are associated variables

When two variables show some connection with one another

What are independent variables

When variables have no evident connection to one antoher

What variable does the explanatory variable affect

the response variable

What is positive association

When both variables move in the same direction

What is negative association

When the variables move in opposite directions

Do graphs show causation or association

association

What are the two types of study that exist?

Observational and Experimental

What are the three principles of experimental design?

Control, randomize, replicate

What needs to exist for something to be an experimental study

A type of treatment

What is another word for an explanatory variable?

Factors

What is a blocking variable

Uncontrollable inherent variables necessary to categorize

What is blocking

Blocking is putting blocking variables into groups and randomizing that which goes into those groups

What is a population

The entire group of interest, all possible members

What is a sample

a subset of the population

What is anecdotal evidence

evidence that consists of anectodes

Should we use anecdotal evidence?

No

What is a census

A census is a sample that consists of the entire population.

Exploratory analysis

When you examine a small part of a whole

Bias

Systematic distortion of sample data that tends to favor one type of result over another

What is non-response

When only a small fraction of the randomly sampled group choose to respond to a survey, the sample may no longer be representative of the population

Voluntary response sample

Occurs when the sample consists of people who volunteer to respond because they have strong opinions. This sample will not be representative of the population

Convenience sample

Individuals who are easily accessible are more likely to be included in the sample

What is a prospective study

collects data as the event in question unfolds

retrospective study

collects data as the event in question is over

What is a simple random sample

Everyone has an equal chance of being selected

Stratified Sample

groups of common characteristics (strata) and a random sample is taken from each stratum

Cluster sample

Not homogenous sample. Each cluster is representative of varied populations and a SRS is taken from each cluster

Multistage sample

1) SRS of initial clusters 2) Make strata from the data from the first SRS and then take another SRS

Systematic sample

Taking a random sample of every k-th subject

What do histograms show

data density

How do you interpret a histogram

See where data is concentrated, its groups, and the frequency of each group

Relative frequency histogram

Histogram with relative frequency (frequency/# of total data values=proportions)

What is modality

peaks in data

The population mean

The mean of not just the sample but of all the population

standard deviation formula

square root of the variance