Chapter 1: Basics of Statistics

Individuals

objects we collect data on

Variables

characteristics being measured

Quantitative variables

numerical values with magnitudes that can be placed in a meaningful order, ex. number of siblings

Categorical variables

names or labels that can be with/without a logical order, ex. favorite color

Statistical method

1. Design

2. Description

3. Inference

1. Design

how data is collected

2. Description

summarizing data

3. Inference

making decisions from data

Population

overarching set of all individuals we want to study, ex. all MLB players

Sample

subset of population we gather data from in order to make inferences about a population, ex. 70 randomly selected MLB players

Subject

individual in a sample, ex. each MLB player in a sample

Parameter

numerical value that summarizes population data, ex. mean, median, range, etc.

Statistic

numerical value that summarizes sample value

Parameter is typically _____

unknown

If we have data, we can calculate the _______

statistic

Sample ________ are estimations from population _________.

Statstics; parameters

µ

population mean (parameter)

x̄

sample mean (statistics)

p

population proportion (parameter)

p̂

sample proportion (statistic)

Proportion

way to express percentage or fraction; can be equivalently expressed as a percentage, decimal, or fraction; between 0-1

Variation

repeating the same process may yield different results each time

Sampling variability

different samples from the same population typically produce statistic that vary slightly