STATS Quiz 1

Statistics

The theory of decision making

Data

Observations

Population

All individuals of interest

Parameter

Numerical characteristic of a population

Sample

Subset of the population

A statistic

Numerical characteristic of a sample

Two types of data

Quantitative (numerical) and Qualitative (categorical)

Discrete (Quantitative data)

finite or countably infinite # of possibilities

Continuous (Quantitative data)

Uncountably infinite # of possibilities

Nominal (level of measurement)

Qualitative, no math can be done

Ordinal (level of measurement)

Qualitative, can be ranked but differences meaningless

Interval (level of measurement)

Quantitative, can be ranked, differences meaningful, 0 is not inherent

Ratio (level of measurement)

Quantitative , can be ranked, differences meaningful, 0 is inherent

Simple Random Sample (SRS)

Every sample of the same size n has the same chance of selection

Stratified Sample

Break population into homogeneous groups and take a SRS from each group proportionally

Systematic Sample

Take every kth person

Cluster sample

Take entire subgroups

Mean and s

Any points outside mean+-3s

5# Summary

Min, max, Q1, M, Q3

Density Histogram

height=fraction ÷bin width