Join Eddie Davila for an in-depth discussion in this video Z transformation, part of Statistics Foundations: Probability.
- [Instructor] Z scores, they're helpful tools. … They help us measure the distance … between each data point and the mean. … By the way, I'm in exercise file 03_06_Begin. … Here's the dataset for the weights of 10 men. … For this dataset we had a mean of 162.6 … and a standard deviation of 35.0. … The Z score for the last data point 232 pounds is 1.98. … This data point was 1.98 standard deviations above the mean … but now let's take this one step further. … First, we're going to assume that the weights of men … in this population are normally distributed. … Knowing this we can now answer this question. … What percentage of men weigh more than 235 pounds? … To answer this, we'll need two things. … First, the Z score for 232 pounds which is 1.98. … Second, we need a normal distribution table. … On this normal distribution table, we find 1.98. … How do we do that? … Go to your chart and in along the left side, … you're going to look for 1.98. … And then along the top, you're going to find 0.08. …
Eddie explains that probability is used to make decisions about future outcomes and to understand past outcomes. He covers permutations, combinations, and percentiles, and goes into how to describe and calculate them. Eddie introduces multiple event probabilities and discusses when to add and subtract probabilities. He describes probability trees, Bayes’ Theorem, binomials, and so much more. You can learn to understand your data, prove theories, and save valuable resources—all by understanding the numbers.