Summer Packet Vocabulary Flashcards
Categorical Variables
The value of the variable is a name or label
Ex. The color of people’s shirts
Quantitative Variables
The value of the variable is a number
Ex. How many people live on Earth
Discrete Variables
They take on any value between 0 and infinity, and has to be a whole number
Continuous Variables
They take on any value between the maximum and minimum values
Univariate Data
When a study only looks at one variable
Bivariate Data
When a study examines the relationship between 2 variables
Population
Includes all elements in a data set
Ex. Citizens in Italy
Sample
Consists of one or more observations drawn from the population
Ex. Weight of 5 year olds, take the weight of 20 5 year olds
Median
Middle value; a simple measure of central tendency
Mean
Average
Formula: x̄=(X1+X1+X1…XN)/N = [ΣXi]/N
Outlier
An extreme value that differs greatly from the other values in the set
Parameter
A measurable characteristic of a population; mean or standard deviation
Statistic
A characteristic of a sample
Range
The difference between the biggest and smallest variable
Interquartile Range
A measure of variability; middle 50% of the data
Formula: Q3-Q1
Variance
A numerical value used to indicate how widely individuals differ in a group vary
Formula: σ2=Σ(xi - µ)2/N
Standard Deviation
The square root of the variance
Formula: σ=√σ2 = √Σ(Xi- µ)2/N
Standard Score (z-score)
Indicated how many standard deviations an element is from the mean
Formula: z = (x - µ)/σ
Symmetry
Can be divided at the center so each half is a mirror image
Unimodal
Distributions with one clear peak
Bimodal
Distributions with two clear peaks
Skewed Left
Distributions with fewer observations on the left
Skewed Right
Distributions with fewer observations on the right
Uniform
When observations in a set of data are equally spread across the range of distribution
