STATS 250

Observational Units

AKA Cases, are the rows in a data matrix. They represent the individual entities or items that are being studied, such as people, things, or events.

Variable

The columns in a data matrix. The characteristics, behaviors, or results measured about a observational unit. There’s 2 types.

Quantitative variables

AKA numerical or measurement variables. If you’re able to compute the average and do math with that variable, it’s quantitative.

Categorical variables

AKA Qualitative variables. You can’t do math with them bc they’re too Crazy. It’s more of the art side of statistics I guess.

Population of interest

The entire population; can even be in the future.

*Ambiguously* it can also be the underlying process in a randomly repeated measurement phenomenon. Like when you’re flipping a coin for an experiment, the real Population of Interest is the friends we made along the way.

Observed Sample

The small portion of the population that was observed due to ethical, realistic, and possible approaches.

Parameter

$\mu\sigma\pi$ The Unknown Truth attribute that describes the entire population. The three parameters are population mean (), a population standard deviation (sigma), and/or a population proportion (pi).

Statistic

$\mu\sigma\pi$ The Known Truth attribute that describes a sample of the entire population. The three statistics are population mean (mew with a hat), a population standard deviation (sigma with a hat), and/or a population proportion (pi with a hat).