 Hi, this is Dr. Don. I have a problem out of Chapter 2 that can be tricky because it uses the empirical rule and stat crunch and Excel don't have built-in functions or formulas or tools to handle it. But we can do it very quickly using the Excel cheat sheet calculator that I have available on my website. Let me show you how to do it. Here's the problem. We're told that the main value of land and buildings per acre from a sample of farms is 1500 and the standard deviation is 200. We're told the data set is bell shaped distribution and we assume the number of farms in the sample is 75. First part is use the empirical rule to estimate the number of farms whose land and buildings per acre are between 1100 and 1900. We're going to go over here to my Excel empirical rule cheat sheet and I've already entered the mean of 1500 the standard deviation of 200 and I'm going to put the sample size in there of 75 and the calculator updates and we can look down and we can see for the number of standard deviations if you remember for the empirical rule it just says that 68% of the data is within one standard deviation plus and minus 95% within plus and minus 2, 99.7 and plus and minus 3 and so that gives us if we look at an even number of standard deviations a lower value and an upper value for each one of those plus and minus standard deviations once we have this data. Now we're asked about 1100 and 1900 and there it is in the calculator and we can see that the 95% of this end of 75 is in that interval and that is a count of 71 which is the answer they want. Part 2 says if we have 22 additional farms how many of these additional farms would you expect to have values in that same 1100 to 1900 per acre? Well here we need to go back and change the end because we've added 22 and we're only interested in that 22 so I'm going to change this to 22 and we drop down again looking for the 1100, 1900 and something happened. Well what happened was I didn't wait half a second to give the calculator a chance to update and it shows that in that interval of 1100 to 1900 95% of that additional 22 which comes up to be an integer value of 21. So I hope that helps learn to use this empirical rule cheat sheet you can get on my website. Hope this helps and if it does help please consider subscribing to my YouTube channel The Stance Files just click on the big red button