<p>I was just wondering which one we should use for the exam and why the form not used is even created.</p>
<p>Use a + bx</p>
<p>Does it matter?</p>
<p>It doesn’t really matter. Just make sure you know which one is the slope and which is the y-intercept with whichever one you use.</p>
<p>Some statisticians like the first form, and some like the second. The AP test likes a + bx, so although it doesn’t actually matter, and shouldn’t affect your score, I’d use it.</p>
<p>Just be wary of how the calculator displays it, so you don’t mix up “a” and “b” when you write it out. Just be consistent; I normally use the ax + b. Good luck!</p>
<p>You should definitely use a + bx, even though essentially they are the same thing. b is always the slope though, and is calculated in normal regressions as r(sy/sx), so I would stick to that to be safe.</p>
<p>Collegeboard and my textbook use a + bx</p>
<p>a + bx should be used</p>