Probability
The branch of mathematics concerning numerical descriptions of how likely an event is to occur. Foundation of statistical inference.
Read More →Descriptive Statistics
Descriptive statistics summarize and describe the main features of a dataset. Key measures include the mean (arithmetic average), median (middle value), and mode (most frequent value). Measures of spread include variance, standard deviation, and interquartile range.
Probability Distributions
A probability distribution describes how probabilities are assigned to outcomes. The normal distribution is the most important continuous distribution, characterized by its bell-shaped curve with mean μ and standard deviation σ. The binomial distribution models the number of successes in n independent Bernoulli trials.
Hypothesis Testing
Hypothesis testing is a formal procedure for deciding whether sample data support a claim about a population. The null hypothesis (H₀) represents the default assumption; the alternative hypothesis (H₁) is what we seek evidence for. The p-value measures the probability of observing results at least as extreme as the data, assuming H₀ is true.
Common tests include the t-test, chi-square test, ANOVA, and z-test, each suited to different data types and research questions.
Regression Analysis
Regression analysis models the relationship between a dependent variable and one or more independent variables. Simple linear regression fits a straight line to data; multiple regression extends this to several predictors. The least-squares method minimizes the sum of squared residuals to find the best-fit line.