Where did I go wrong on this math problem? (question, my answer and correct answer given)

After looking at this presentation:
http://www.wisc-online.com/objects/ViewObject.aspx?ID=QLT1102
I'd say there isn't a single correct answer.

Ah! I see. I calculated the width wrong.

*sigh* something's still wrong.

max-min=
74-67=1.4

class width=1.4

But the professors class width =1.5

Why? If you were to round it to the nearest integer, wouldn't it be 1, if anything? Why round up? I'd understand if it was 1.48, but it's simply 1.4

You got me. Some of the decisions in the the tutorial were arbitrary. Like I said, I don't think there is a single correct answer.

Okay. Well, thank you for your help! I really appreciate it! You helped a lot!