Khan Academy

Sample variance (K-A)

Estimating mean and median in data displays (K-A)

Visually assessing standard deviation (K-A)

Impact on median & mean: increasing an outlier (K-A)

Impact on median & mean: removing an outlier (K-A)

Mean as the balancing point (K-A)

Missing value given the mean (K-A)

Review and intuition why we divide by n-1 for the unbiased sample variance (K-A)

Simulation providing evidence that (n-1) gives us unbiased estimate (K-A)

Simulation showing bias in sample variance (K-A)

Unbiased estimate of population variance (K-A)

Why we divide by n – 1 in variance (K-A)

Density curve worked example (K-A)

Density Curves-video (K-A)

Median, mean and skew from density curves (K-A)

Worked example finding area under density curves (K-A)

How parameters change as data is shifted and scaled (K-A)

Transforming data problem (K-A)

Finding z-score for a percentile (K-A)

Standard normal table for proportion above (K-A)

Standard normal table for proportion below (K-A)

Standard normal table for proportion between values (K-A)

Threshold for low percentile (K-A)

Basic normal calculations (K-A)

Normal distribution problems: Empirical rule (from ck12.org) (K-A)