Hunter counted the number of silver cars that he saw in a public car park from Monday to Friday of one week. He draws a bar chart to show his results. Identify two mistakes that Hunter has made.
The frequency table tells us that on Monday, there were 10 silver cars. On Tuesday, they were 11 silver cars. On Wednesday, Hunter counted eight silver cars. On Thursday, there were seven. And on Friday, there were 12 silver cars. He has then drawn this information on the bar chart. The frequency, in this case, is the number of silver cars. Monday’s bar has a height of 10, Tuesday of 11, Wednesday of eight, and so on.
We have been asked to find two mistakes that Hunter made when drawing the bar chart. Let’s first look at the vertical axis, number of silver cars. We can see here that there are two squares between zero and two silver cars. This means that at this part of the graph one square represents one car. However, this is not the case for the whole of the axis. There are only two squares between four and eight cars. This means that in this portion of the graph one square represents two cars. The number six has been missed out on the 𝑦-axis. The first mistake that Hunter has made is that there is unequal labelling on the 𝑦-axis. It jumps from two to four and from four to eight.
Let’s now look at the horizontal or 𝑥-axis which has the days of the week. Monday, Tuesday, Wednesday, Thursday, and Friday. Each of these bars should have the same gap or no gap at all between them. As all of these gaps are different widths, we can say that Hunter’s second mistake is inconsistent spacing between the bars. These are the two mistakes that Hunter has made when drawing a bar chart. When answering any question like this, it is important to look at both axes carefully.