AP Stats Midterm - The Basics

Qualitative Data

a name or a label, ex. The color of a ball (e.g., red, green, blue) or the breed of a dog (e.g., collie, shepherd, terrier)

Quantitative Variables

a number, ex. number of people in the city, number of students in a school

Discrete Variables

can’t take on any value between its minimum value and its maximum value, ex. 5, 6

Continuous Variables

can take on any value between its minimum value and its maximum value, ex. 5.5, 6.3

Univariate Data

working with one variable, ex. weight

Bivariate Data

working with two variables, ex. height and weight

Population

includes all elements from a set of data

Sample

one or more observations drawn from the population

Parameter

measurable characteristic of a population, ex. mean or standard deviation

Statistic

measurable characteristic of a sample

Simple Random Sampling

a technique used in statistics to select a sample from a larger population in a way that every individual or element has an equal chance of being chosen

Median

the middle value

Mean

average of all the values

Outlier

an extreme value that differs greatly from other values

Range

the difference between the largest and smallest values in a set of values

Interquartile Range (IQR)

the difference between the largest and smallest values in the middle 50% of a set of data

Variance

average squared deviation from the population mean

Standard Deviation

square root of the variance, statistical measure that shows how spread out or dispersed a set of data points are from the mean

Quartiles

divide a rank-ordered data set into four equal parts

Standard Score/z-Score

indication of how many standard deviations an element is away from the mean