Instrumental Variables and Two-Stage Least Squares: Solving the Endogeneity Problem

Econometrics, Regression Analysis, Statistics

Instrumental Variables and Two-Stage Least Squares When your data is lying to you — and how to get the truth anyway Here’s the problem with just running a regression Imagine you want to know: does more education make you earn more? Simple — just look at the...

What is Variance in Statistics? Formula, Examples and Interpretation

Statistics

If the difference between squared deviations and standard deviation still feels abstract, the fix is worked repetition. The Statistics Made Simple Practice Questions workbook has a full section of variance and standard deviation drills with worked answers. Statistics...

Central Limit Theorem Explained: Why It’s the Foundation of Statistics

Statistics

The CLT is the engine behind every confidence interval and t-test you’ll ever run, and it’s one of the most tested concepts across AP, A-Level and undergraduate exams. The Statistics Made Simple Practice Questions workbook has a dedicated chapter of CLT...

Correlation vs Causation: Key Differences, Examples and Why It Matters

Statistics

Distinguishing correlation from causation is a skill examiners test constantly, and it only sharpens with repetition. The Statistics Made Simple Practice Questions workbook has scenario-based questions with full mark schemes for exactly this kind of critical...

Type I and Type II Errors in Statistics: Clear Explanation with Examples

Statistics

Recognising Type I vs Type II scenarios quickly is a skill built through repetition, not memorisation. The Statistics Made Simple Practice Questions workbook drills this with exam-style questions and full mark schemes. Statistics · Hypothesis Testing Type I and Type...

Hypothesis Testing: A Complete Step-by-Step Guide with Examples

Statistics

Hypothesis testing only clicks once you’ve run the five steps yourself, repeatedly, on new scenarios. The Statistics Made Simple Practice Questions workbook has dozens of worked hypothesis tests with full mark schemes. Statistics · Hypothesis Testing Hypothesis...

Confidence Intervals Explained: Definition, Formula and How to Interpret Them

Statistics

The interpretation trap in this post catches almost every student at least once. The Statistics Made Simple Practice Questions workbook has interval-construction and interpretation questions with full worked answers. Statistics · Estimation Confidence Intervals...

P-Value Explained: What It Means and How to Interpret It Correctly

Statistics

P-values are the most tested, most misread concept on any statistics exam. The Statistics Made Simple Practice Questions workbook has over a hundred hypothesis-testing questions built to catch every one of the classic misreadings. Statistics · Hypothesis Testing The...

Descriptive Statistics in Economics: Mean, Variance, Skewness, and How Data Misleads

Statistics

Descriptive Statistics in Economics Before you do any fancy analysis — first, just look at your data! Why bother with descriptive stats? Imagine you’re a doctor. Before you diagnose someone, you take their temperature, check their pulse, look at their weight....

Normal Distribution Explained: Properties, Z-Scores and Real-World Examples

Statistics

Z-scores and the normal table look intimidating the first time and become completely mechanical by the tenth. The Statistics Made Simple Practice Questions workbook has a full chapter of normal distribution problems to get you there. Statistics · Probability...