Quandaries and Queries 

Name: Rebecca Question: Hi I have to use a suitable computer package (ie. Excel) to work out the mean and standard deviation of the following: Price Range No of Houses No of Houses £`000 Area 1 Area 2 45 an under 50 4 5 50 and under 55 7 12 55 and under 60 14 16 60 and under 70 19 18 70 and under 80 8 3 80 and under 100 5 2 I have used excel to work out mean and standard deviation before, but not in a more complicated example like this. Any advice on where to start would be greatly appreciated. Hi Rebecca, The problem, as I see it, is that you don't have all the information. For example, in Area 1 you know that 4 houses sold for a price between £45,000 and £50,000 but you don't know the exact prices. The usual technique here is to estimate these prices and say that the 4 houses sold for a price that is midway between £45,000 and £50,000, that is £47,500. Create another column which contains midpoints of the "Price Range" column. Use these values to calculate the mean and standard deviation, but weighted by the "No of houses" columns. For example for the "Area 1" column you would have 4 values of £47,500, 7 values of £52,500, and so on. Penny 

