Confounding Variable

Variable related to both the treatment and the outcome

Conditional Probability

Probability of an event occurring given another event has already occurred

Chi-Square Goodness of Fit Test

Tests if sample distribution fits a population distribution

ANOVA (Analysis of Variance)

Compares means of three or more groups

Confounding vs Lurking Variable

Confounding: affects both variables; Lurking: affects outcome but not considered in analysis

Bimodal Distribution

Distribution with two different modes

Cluster Sampling

Population divided into clusters; randomly select clusters, then sample all in cluster

Bayes' Theorem

Calculates probability of an event based on prior knowledge of conditions

Chi-Square Test for Independence

Tests if two categorical variables are independent

Control Group

Group in an experiment that does not receive treatment

Addition Rule for Probability

P(A or B) = P(A) + P(B) - P(A and B)

Blinding

Participants unaware of whether they are receiving treatment or placebo

Box Plot

Displays five-number summary (minimum, Q1, median, Q3, maximum)

Correlation Coefficient

Measures strength and direction of linear relationship between two variables

Coefficient of Determination

R-squared; proportion of variance in the dependent variable predictable from the independent variable

Alternative Hypothesis

Statement researcher wants to prove

Conditional Probability Formula

P(A|B) = P(A and B)/P(B)

Cumulative Frequency

Sum of frequencies for that category and all previous categories

Central Limit Theorem

Sampling distribution of the sample mean approximates a normal distribution as sample size increases

Categorical Data Analysis: Chi-square Test

Assesses relationships between categorical variables

Convenience Sampling

Use results that are easy to get

Biased vs Unbiased Estimator

Biased: systematically off; Unbiased: accurate on average

Combination

Selection of objects without regard to order

Binomial Distribution

Probability distribution of number of successes in a fixed number of trials

Confidence Interval

Range of values believed to contain population parameter with a certain level of confidence