In this tutorial we're looking at how to draw histograms. The histograms will always be drawn with bars of equal width, this means that frequency rather than frequency density can be used for the vertical scale. The dataset here is the number of goals scored and the number of points for teams in the Premiership in a season. You may find it easiest to reset the calculate before starting, so that your screen matches the one in the video, but it will delete any data that you've already typed in.
To type the data into lists one and two choose stats mode. Type the x values first using the execute key after each number to move the cursor down. When you've typed all the x values move the cursor to the right and then type the list of y numbers in list two.
To graph the data, choose graph and go to set. To select the type of graph, choose graph one, scroll down and choose histogram from the second list of options and list one is the default setting. Execute to save. Go back to set for graph two, scroll down to choose histogram and choose list two. Scroll down to color to change the appearance of the histogram. Choose color and execute brings up a list of options. Scroll to the color you want, execute then exit to go back to the settings and execute again.
Before you draw your histograms, you will need to know the lower class boundary for the first class, known as the start for the histogram, and the class width, which is the same for every class. You can easily change these to get the histogram which suits your data best. I'm going to use 10 for the start and 20 for the class widths. You may find settings from previous histograms will come up and you can just overtype them with new values. Press graph one and enter the values to choose the class boundaries. I've used to 10 for the start and 20 for the class width, and enter and then view window can be used to change the scales. If you scroll down for the scale for x and enter 10 and execute and then scroll down again to find y. And this will be frequency, so enter one and execute. Exit this screen and reselect graph one. I'm using new class boundaries here and execute.
There may be times when you want to see histograms from graph one and graph two together. So exit and choose select. You need to switch on graph one and down to graph two and then draw. Just press execute to redraw with existing settings and oth histograms are drawn with graph two on top of graph one.
The video tutorial video on bivariate data also uses this dataset, so you might want to check it out while you've still got the data on your calculator You can find other the tutorials and other resources at education.casio.co.uk