Histogram – basics
4. Create a histogram of daily users
More on histograms

Instruction

It's your turn to construct a histogram on your own.

You will prepare a histogram of daily users for websites in the information category. If you look at the Datasets tab, you will see that our ten information websites have the following numbers in the user column:

1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000

To create a table the histogram is based on you have to compute the ends of each bin. The bottom bin has to start below or at the minimum of the dataset. The top bin has to end above the maximum of the dataset. For this dataset:

2, 3, 5, 7, 11, 13, 17, 19, 22
the bottom bin can start at 2, and the top bin can end at 23.

There are nine elements in our dataset, so we can create 3 equal-width bins. The width of each bin is the difference between the end of the top bin and the beginning of the bottom bin, divided by the number of bins. Using our example above, this would be: (23-2)/3=21/3=7 . The intervals for the histogram, expressed in interval notation, are: [2, 2+7) = [2,9), [9, 9+7) = [9,15), [15, 15+7) = [15,23). Finally, the table for the histogram looks like this:

Bin Count Values
[2,9) 4 2, 3, 5, 7
[9; 15) 2 11, 13
[15; 23) 3 17, 19, 22