We start thinking about how we can plot revenue and profit as a bar graph, when Calvin stops by. He takes a look at what we have. "Oh, I forgot. Sara sent a follow-up e-mail. There were a couple of categories that were left out of the spreadsheet. Let me forward that to you guys."

Calvin looks for the e-mail on his phone while he keeps talking, "Also, can you create a chart showing revenue grouped by product categories? She'll send over the data later this afternoon. OK, sent. I'll check back later," he says while walking out of the office.

We receive the second e-mail and open the updated spreadsheet. There are two new categories and their totals are much higher than the others. We can see why Sara is so concerned:

With all these categories on the x axis, we will...