Statistics Fundamentals Vocabulary

Vocabulary flashcards covering key statistical terms, calculations, data types, and levels of measurement from lecture notes.

Relative Frequency

The percentage of data in a category, calculated as $\left(\frac{\text{frequency in category}}{\text{total frequency}}\right) \times 100\%$. The sum of the relative frequency percentages should be $100\%$, though rounding is allowed.

Class Width

The difference between two consecutive lower class limits, calculated by taking the lower limit of the second class and subtracting the lower limit of the first class (e.g., $30 - 25 = 5$).

Class Midpoint

The middle value of a class interval, calculated by adding the lower and upper limits and dividing by $2$ (e.g., $\frac{25 + 29}{2} = 27$).

Class Boundaries

The numbers used to separate classes without gaps, calculated by subtracting $0.5$ from the lower class limit and adding $0.5$ to the upper class limit (e.g., for $25 - 29$, boundaries are $24.5$ and $29.5$).

Mean

The average of a data set, calculated by adding all numbers together and dividing by how many numbers there are.

Median

The middle number in a data set when the numbers are placed in numerical order.

Mode

The number that appears most frequently in a data set, or the value that keeps repeating.

Range

The difference between the extreme values in a data set, calculated as the highest number minus the lower number.

Population

The entire group that you care about and wish to study.

Sample

A smaller group selected or taken directly from the population.

Parameter

A numerical measurement describing a characteristic of a population.

Statistic

A numerical measurement describing a characteristic of a sample.

Variable

The specific attribute or quantity that you are measuring.

Qualitative Data

Data comprised of categories that do not measure an amount (e.g., hair color, major, type of car, eye color).

Quantitative Data

Data represented by actual numerical values (e.g., age, weight, exam score, number of children).

Discrete Data

Quantitative data consisting of values that you count.

Continuous Data

Quantitative data consisting of values that you measure.

Nominal Level of Measurement

A measurement scale consisting of named categories with no natural ordering.

Ordinal Level of Measurement

A measurement scale consisting of categories that have a logical order (e.g., poor $\rightarrow$ fair $\rightarrow$ good $\rightarrow$ excellent).

Interval Level of Measurement

A measurement scale with numbers having meaningful differences between values, but lacking a true zero point.

Ratio Level of Measurement

A measurement scale with numbers having meaningful differences and a true zero point.

Cumulative Frequency

The running total of frequencies in a frequency distribution, determined by adding the frequency of a class to the frequencies of preceding classes.