This task has students approach a function via both a recursive and an algebraic definition, in the context of a famous game of antiquity that they may have encountered in a more modern form. The content underlying the algebra is the sum of the first n natural numbers (also known as the nth triangular number.

Total solar eclipses are quite rare, so much so that they make the news when they do occur. This task explores some of the reasons why. Solving the problem is a good application of similar triangles

The typical system of equations or inequalities problem gives the system and asks for the graph of the solution. This task turns the problem around. It gives a solution set and asks for the system that corresponds to it. The purpose of this task is to give students a chance to go beyond the typical problem and make the connections between points in the coordinate plane and solutions to inequalities and equations. Students have to focus on what the graph is showing.

Sal solves a linear system with 3 variables by representing it with an augmented matrix and bringing the matrix to reduced row-echelon form. Gaussian Elimination is the method, reduced row echelon is just the final result.

The purpose of this task is to have students compute and interpret an expected value, and then use the information provided by the expected value to make a decision. The task is designed to encourage students to communicate their findings in a non-technical form in context.

Determining whether 3 vectors are linearly independent and/or span R3. Created by Sal Khan.

The purpose of this task is to allow students to demonstrate an ability to construct boxplots and to use boxplots as the basis for comparing distributions. The solution should directly compare the center, spread, and shape of the two distributions and comment on the high outlier in the northbound data set.

This 8-minute video lesson provides analysis of variance 1: Calculating SST (Total Sum of Squares). [Statistics playlist: Lesson 75 of 85]

This 13-minute video lesson provides analysis of variance 2: Calculating SSW and SSB (total sum of squares within and between). [Statistics playlist: Lesson 76 of 85]

This 10-minute video lesson provies analysis of variance 3: Hypothesis test with F-statistic. [Statistics playlist: Lesson 77 of 85]

This 12-minute video lesson plays with the formula for variance of a population. And looks at alternate variance formulas. [Statistics playlist: Lesson 16 of 85]

This 7-minute video lesson gives formulas for the Bernoulli Distribution Mean and Variance. [Statistics playlist: Lesson 42 of 85]

This 10-minute video lesson explains box and whisker plots. [Statistics playlist: Lesson 9 of 85]

This 8-minute video lesson takes problems from CK12.org to discuss using the Empirical Rule with a standard normal distribution. [Statistics playlist: Lesson 33 of 85]

This 6-minute video lesson uses problems from CK12.org to provide more Empirical Rule and Z-score practice. [Statistics playlist: Lesson 34 of 85]

This 10-minute video lesson takes some problems from CK12.org and uses the empirical rule (or 68-95-99.7 rule) to estimate probabilities for normal distributions. [Statistics playlist: Lesson 32 of 85]

This 11-minute video lesson takes some problems from CK12.org and discusses of how "normal" a distribution might be. [Statistics playlist: Lesson 30 of 85]

This 10-minute video lesson shows how to calculate R-squared to see how well a regression line fits the data. [Statistics playlist: Lesson 70 of 85]

This 10-minute video lesson introduces the chi-square distribution. [Statistics playlist: Lesson 72 of 85]

This 3-minute video lesson provides clarification of the previous video on the confidence interval for difference of means. [Statistics playlist: Lesson 57 of 85]