## Two-sample Difference Between Proportions Z-test

Problem https://youtu.be/_SvoDf7Toi4 https://youtu.be/XWLsrGtLfAo

## One-sample Sigma Known z-test for the Mean

Joel, I have not checked all your calculations, but the process you used looks good. I note that this is a problem where you are given a lot of raw data. Which technology did you use? I ask because problems where you have to manually enter a lot of raw data often lead to mistakes […]

## Simple One-sample z-test for the Mean when Sigma is Known

Here is a way to do a simple one-sample z test when we know the population standard deviation sigma. If this was a left tail test as indicated by an < in the alternative hypothesis, the standardized test statistic (z) of -1.753 falls in the rejection region below the z-critical of -1.645 and that would […]

## 7.4.5 Single Sample Hypothesis Test for a Proportion

Here is the screenshot of the basic StatCrunch solution. [My Excel calculator for running this test is found here.] As always for proportion problems, we have to check first to be sure np and nq or n*(1-p) are both > 5. If they are, we can use the normal approximation to the binomial (a proportion […]

## Hypothesis Test for Mean Difference using StatCrunch

I see a lot of students struggle with recognizing what a problem statement is asking them to do. Consider this problem: What do you get from that reading? I get:

## The Stones at Big Thunder Mountain!

No, not the Rolling Stones, though these stones were rolling. Y’all know I love stats, but this article popped up on my FB feed tonight and I have to share it. It is about some nifty research conducted while riding Big Thunder Mountain at Disney World’s Magic Kingdom. It seems a certain urologist noticed that […]