 Hi folks, this is Dr. Don. I have a problem from Chapter 2 about a frequency distribution. We are given this frequency distribution but we do not have the actual data it was developed from. I have gone over how to create a frequency distribution when given a data set in other videos. Here we are told the distribution is of the heights of 18 students and we are asked to approximate the mean height of the students. Now if we had the original data this would be a trivial exercise. But we don't so we are going to create a facsimile of the data using Excel. I'm going to get the data into my Excel workbook by clicking on the small blue rectangle and copying the data to the clipboard. If you don't already have Excel open you can open in Excel instead. The data should be highlighted in blue but if it isn't use your mouse to select all of it including the titles. If the data is highlighted it should already be copied to the clipboard. But I like to be sure so I use the control plus the C key to copy the data to the clipboard. I navigate to my open workbook and I always paste the data into the first cell on the top left. Now this is just a good habit to get into if you're working with many types of these problems and want to be able to easily reuse your workbooks on new but similar data sets. We start by finding the midpoint of the bends or classes in the frequency distribution. The bend widths are two inches here so the midpoint is obviously 61 in the first bend. If you had more complex bend limits you could find the midpoints using your calculator. I'll label column C midpoints and place them here 61, 64, 67 and 70. We will need the total count of heights in. We were given 18 in this problem but if you weren't use the Excel SUM function to find it. Click in cell B6 and enter an equal sign and begin typing SUM. Select the SUM function by double left clicking and then select the range you want to total. Hit enter and we have our total of 18 heights. Next we need to find the weighted values of each bend using a simple formula in Excel. Click in the first cell, enter equal and left click on the frequency, multiplying it by entering an asterisk and left click on the midpoint, hit enter. Now drag that formula down for the other bends. Find the sum of the weighted values by using the SUM function again. Left click and cell D6, enter equal SUM and select the range. Finally find the approximate mean by dividing that SUM by the count N. Click in the desired cell, enter an equal sign and left click on the weighted SUM. Enter a slash to divide and left click on the N, hit enter. The approximate mean heights of the students in the sample is 65 inches. In my stat lab be sure to enter the exact number of decimal places specified which is zero here for the nearest inch. For your class notebook I like to finish up by using the formula text function to show the formulas I have used. Left click in the cell, enter equal formula and then select formula text. Left click on the cell of interest and hit enter. Here I will drag that formula down to show all the formulas used in this workbook. Whoops there is one more. Left click in the cell beneath the count and use formula text again. You can click in any cell, it doesn't have to be immediately on the left or even adjacent, although you may need to add some notes to tell you which cell you're referring to if it's not obvious. Okay that's it. I hope this helps.