by Dawn Wright | Nov 25, 2018

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...
by Dawn Wright | Nov 21, 2018

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...
by Dawn Wright | Nov 2, 2017

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...
by Dawn Wright | Apr 5, 2017

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 phrase “Can the engineer support the claim…” tells me this is to be a hypothesis test. The second part...
by Dawn Wright | Sep 28, 2016

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...