Confidence Intervals: Free Course

About this course

An interval estimate expresses uncertainty around a sample statistic. This course develops confidence levels, margins of error, proportion intervals and t intervals for means. Study the complete public source playlist from Khan Academy in English, with all 14 recordings in the on-site classroom. Original lesson titles, source order and repeated entries are preserved.

Course at a glance

What you’ll learn

• Interpret confidence levels using repeated sampling.
• Construct intervals for a proportion and a mean.
• Recognize when paired observations require differences.
• Relate sample size, confidence and margin of error.

Skills you’ll gain

• Confidence intervals
• Margin of error
• T statistics
• Sample-size planning

Course Overview

Simulation examples clarify what repeated-sampling confidence means. Critical values, standard errors and margins of error then connect that interpretation with interval construction. The t-statistic recordings explain why inference for a mean differs when population variability is estimated from the sample. Paired-data examples apply a mean interval to within-pair differences rather than treating related observations as unrelated groups. Sample-size lessons reverse the usual calculation by starting with a desired precision. Conditions are examined explicitly, so the method is more than substituting numbers into a formula. A confidence level describes the procedure over repeated samples, not a probability assigned to a fixed parameter after the interval is computed.

How to study the course

• Videos 1–3: this part of the source list includes “Example constructing a t interval for a mean” through “Sample size for a given margin of error for a mean”. Define the question and the observations. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.
• Videos 4–7: this part of the source list includes “Conditions for confidence intervals worked examples” through “Conditions for valid t intervals”. Check the assumptions behind a method. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.
• Videos 8–10: this part of the source list includes “Interpreting confidence level example” through “Confidence interval simulation”. Connect a calculation with a plain-language interpretation. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.
• Videos 11–14: this part of the source list includes “Simulation showing value of t statistic” through “Example constructing and interpreting a confidence interval for p”. Describe uncertainty and limits of a conclusion. Keep a brief working note, revisit an unclear explanation and test one example before moving to another part of the material.

Who is this for?

This course suits students, analysts and readers who want to understand the specific statistical methods in the course. It also provides a recorded reference for revisiting a topic after an earlier lesson or study attempt. Choose examples appropriate to your background and allow time to work through the method instead of judging understanding only by how familiar the terminology sounds.

Before you start

Basic arithmetic and familiarity with tables and graphs are helpful. More advanced probability or inference topics assume the prerequisite methods shown in the recordings.

Put the lessons into practice

Use fictional sample summaries to construct one proportion interval and one mean interval. Write an interpretation naming the population parameter and the confidence procedure. Explain what changes when the confidence level rises. For paired observations, form the differences first and explain why that choice matches the study design.

This optional study activity is provided by WikiFree for independent practice. Keep your working notes and use the relevant classroom recording to check a step, definition or interpretation. It is not an instructor-marked assignment.

Certificate / Assessment

Watching the public videos and using WikiFree completion tracking does not award a certificate, academic credit, an examination voucher or instructor assessment. Use your practice output to review what you can explain and repeat independently. The recorded lessons provide study material; completion tracking records your progress through that material.

Frequently asked questions

Provider: Khan Academy. Videos play from the Khan Academy channel on YouTube.