Modeling Data Distributions: Free Course

About this course

Density curves turn the shape of a distribution into a probability model. This course develops normal distributions, percentiles, standardized scores and areas under curves. 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 area under a density curve.
• Relate percentiles to cumulative relative frequency.
• Calculate and compare z-scores.
• Use a normal table to find proportions and cutoffs.

Skills you’ll gain

• Normal distribution
• Density curves
• Percentiles
• Z-scores

Course Overview

The source combines qualitative normal-distribution reasoning with calculations using the standard normal table. Density-curve examples distinguish area from height and connect the positions of the mean and median with skewness. Percentiles and cumulative relative-frequency graphs express location within a distribution. Standardizing with a z-score then permits comparisons measured in standard-deviation units. Both lower-tail and upper-tail table examples are included, alongside inverse questions that ask for a cutoff corresponding to a percentile. Treat the normal distribution as a model whose suitability matters; an arbitrary dataset does not become normal simply because a standardized score can be calculated.

How to study the course

• Videos 1–3: this part of the source list includes “ck12.org normal distribution problems: Qualitative sense of normal distributions” through “Median, mean and skew from density curves”. 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 “Calculating percentile” through “Density Curves”. 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 “Finding z-score for a percentile” through “Analyzing a cumulative relative frequency graph”. 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 “ck12.org normal distribution problems: z-score” through “Threshold for low percentile”. 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

Choose a fictional normal model with a stated mean and standard deviation. Standardize two observations, find a lower-tail proportion and solve for a percentile cutoff. Sketch the corresponding shaded regions before using a table. Explain the difference between the height of the curve at a point and the probability represented by an interval.

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.