Correlation Coefficient
Measures strength and direction of linear relationship between two variables
Blinding
Participants unaware of whether they are receiving treatment or placebo
Cumulative Frequency
Sum of frequencies for that category and all previous categories
Binomial Distribution
Probability distribution of number of successes in a fixed number of trials
Control Group
Group in an experiment that does not receive treatment
Cluster Sampling
Population divided into clusters; randomly select clusters, then sample all in cluster
Confidence Interval
Range of values believed to contain population parameter with a certain level of confidence
Conditional Probability
Probability of an event occurring given another event has already occurred
Bayes' Theorem
Calculates probability of an event based on prior knowledge of conditions
Combination
Selection of objects without regard to order
Convenience Sampling
Use results that are easy to get
Alternative Hypothesis
Statement researcher wants to prove
Bimodal Distribution
Distribution with two different modes
Chi-Square Goodness of Fit Test
Tests if sample distribution fits a population distribution
Confounding Variable
Variable related to both the treatment and the outcome
Chi-Square Test for Independence
Tests if two categorical variables are independent
Addition Rule for Probability
P(A or B) = P(A) + P(B) - P(A and B)
Confounding vs Lurking Variable
Confounding: affects both variables; Lurking: affects outcome but not considered in analysis
Categorical Data Analysis: Chi-square Test
Assesses relationships between categorical variables
Coefficient of Determination
R-squared; proportion of variance in the dependent variable predictable from the independent variable
Box Plot
Displays five-number summary (minimum, Q1, median, Q3, maximum)
Central Limit Theorem
Sampling distribution of the sample mean approximates a normal distribution as sample size increases
Conditional Probability Formula
P(A|B) = P(A and B)/P(B)
ANOVA (Analysis of Variance)
Compares means of three or more groups
Biased vs Unbiased Estimator
Biased: systematically off; Unbiased: accurate on average