Statistics Lesson 1.1-2.1

Statistics

The science of collecting, organizing, analyzing, and interpreting data to make informed decisions.

Population

The total group of interest in a statistical study.

Sample

A selected subset of the population used for analysis.

Parameter

A numerical description of a characteristic of an entire population.

Statistic

A numerical description of a characteristic of a sample.

Descriptive Statistics

Summarizes data characteristics without making inferences beyond the data set.

Inferential Statistics

Uses a sample to draw conclusions about a population.

Qualitative Data

Data that represents categories that cannot be quantified.

Quantitative Data

Data that can be quantified and analyzed mathematically.

Nominal Level of Measurement

Categorical data with no meaningful order (e.g., eye color).

Ordinal Level of Measurement

Categorical data with a meaningful order but no measurable differences (e.g., satisfaction levels).

Interval Level of Measurement

Numerical data with equal intervals but no true zero (e.g., temperature in °F).

Ratio Level of Measurement

Numerical data with equal intervals and a true zero (e.g., height, weight).

Observational Study

A study where the researcher observes and measures characteristics without modifying conditions.

Experimental Design Principles

Includes controlling confounding variables, randomization, and replication.

Random Sampling

A sampling method where every member of the population has an equal chance of being selected.

Stratified Sampling

Dividing the population into strata and randomly sampling from each stratum.

Cluster Sampling

Grouping the population into clusters and randomly selecting entire clusters for study.

Systematic Sampling

Assigning numbers to population members and selecting at regular intervals from a randomly chosen starting point.

Frequency Distribution

A table showing the number of entries within specific classes or intervals.

Cumulative Frequency

The sum of a class's frequency and all previous classes' frequencies.

Histogram

A bar graph representing the frequency distribution of a dataset.

Relative Frequency

The portion or percentage of data that falls within a specific class.

Dot Plot

A graphical display of data using dots to represent frequency.

Scatter Plot

A graph displaying paired data sets as points in a coordinate plane to show relationships.

Mean

The average of a data set found by dividing the sum of all entries by the number of entries.

Median

The middle value in a data set when the data is arranged in order.

Mode

The value that occurs most frequently in a data set.

Treatment Group

A part of a population in an experiment that receives the treatment.

Control Group

The group in an experiment that does not receive the treatment.