So let’s move this down so we can see a little bit more what we’re doing. So the easiest way for me to get into StatCrunch is just to put my data in, although once I get my data here into StatCrunch, see, the first thing I’m going to do is get rid of my data because I don’t need the data I just need StatCrunch. So this is what I need to put into StatCrunch. I’ll put the standard deviation just below it, and there’s my standard deviation. Now down here under the height column, I’m going to put in an AVERAGE function, I’m going to select all those data points, then close my parenthesis - there’s my average. So I’m just going to scroll down here, select the row, delete all that. To do that, the first thing I’m going to do is get rid of all the male data points here because we don’t need them. So first I’m going to get the sample mean and standard deviation and put those values into StatCrunch. We want a normal distribution, and the mean and standard deviation are coming from our sample data itself. Now, Part B says, “Assuming a normal distribution with mean and standard deviation given by the sample mean and standard deviation, find the probability of a randomly selected height belonging to each class.” So the probabilities are going to come out of our distribution calculator in StatCrunch that’s the easiest way to get this. Beyond that you get all the male data points. “Greater than 168.35" - so this is the last category, so I’m going to go up to the last female data point, which is this one right here. 161.75 would be there, and 41 is the count. I just put in a 20 there.Īnd now I’m going to do the same thing for each of the different other classes, so I’m going to select the next cell here, and go down to 161.75. So that made the counting super easy for me. And if I look down here at the bottom of my Excel window, I see that the count here is 20. So now I’ve selected all those data points that are less than 155.15. So I’m going to hold down the Shift key on my keyboard and press the left key on my mouse. So 155.15 is going to be every data point up to this one. So I’m going to select that first cell with my data point here in my data, and then I’m going to scroll down to where I get the - let’s see, 155.15. So we want to count the number of data points that are less than 155.15 that’s our first category or class here. And that’s all we’re doing with frequency is we’re getting counts of measurements that fall within each of these different classes or categories. The other thing that is nice about Excel is that it makes counting really easy. So I hit OK, and now everything is automatically sorted. This will actually help us to count to get the frequencies that we need to fill in our table here for our answer fields. And then I’m going to add a level so that within the females I’m going to actually sort by height. And then here in the sort dialog box, I first want to sort by gender so we can get all the males out of the way. So to do that, I’m going to come up to menu here - I’m coming off screen a little bit so you can’t see, but I’m selecting Data. And what I want to do now is actually sort this data out. So I’ve already pre-loaded the data here into Excel. And that’s what we want because it makes our job a little easier. The sort feature in StatCrunch only lets you sort one level at a time whereas with Excel, it will let you sort multiple levels at the same time. So the thing is I want to actually use Excel because we could do it in StatCrunch but StatCrunch is really clunky, and especially when it comes to sorting data. So we’ve got two different sortings to do, and so to do that, I want to open the data in Excel. Notice also here the height data is actually unsorted itself too. We’ve got to sort through all this data to get just the heights for the females we weren’t asked for the heights of the males, just the females. Here the ones are males, so the zeros must be females. So the gender variable is a dummy variable where you’ve basically got two options: One option is a zero and the other is a one. If we look at our data in our table here, notice how we’ve got females mixed in with males. OK, Part A is asking us to “enter the observed frequencies in the table below.” So here they’ve got different categories or classes for height, and then we’re asked to fill in the different frequencies.
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