Learn statistics through clear guides, worked examples, formulas, assumptions, interpretation, and practical reporting advice.
Sample standard deviation measures how spread out the values in a sample are around the sample mean. It is used when your observations represent only part of a larger population.…
Population standard deviation measures how spread out all values in a population are around the population mean. It is used when your data include every member, item, score, or observation…
A one-proportion z-test is one of the hypothesis tests used to determine whether a sample proportion is significantly different from a hypothesized population proportion. It is suitable when the outcome…
When performing a hypothesis test for a sample mean where the population standard deviation is known, or when performing one-proportion or two-proportion z-tests, you will often come across the z…
When reading survey results, especially in published work, you might come across a percentage followed by a ± value. For instance, results from a poll may show that 58% ±…
The population mean is the average value of all observations in the entire group you want to study. You use it when your data includes every member, item, score, or…
The sample mean is the average value of observations collected from a sample of a larger population. It is commonly used to summarize sample data and estimate the population mean…
Slovin's formula is a statistical formula that is commonly used in research to determine the minimum sample size (n) for a study, when the population size (N) and acceptable margin…
A chi-square table (χ² table), also known as a chi-square critical value table or chi-square distribution table, is a statistical reference table used to determine critical values for chi-square (χ²)…
A 5-number summary is a simple way to describe a dataset using 5-key statistics: the Minimum, First Quartile (Q1), Median (Q2), Third Quartile (Q3), and Maximum. Summarizing your data using…