<p>@ olleger
but weren’t they asking for the mean of the data and not the frequencies? unless I misread YET ANOTHER question 
:(</p>
<p>Are you sure? Apparently there was a -q that makes more sense…</p>
<p>sorry, typed that wrong. it’s -q, but what letter was that?</p>
<p>@ ilikebannanas.
The two columns were named value and frequency… <em>i think</em> they were just talking about the mean of the frequency column</p>
<p>“Uhh, actually it was pi…the equation was 2sin(2x - 1), and the period of a sin graph = 2pi / k. 2pi/2 = pi.”</p>
<p>It was 1/pi and it was 4sin(2x-1) not 2sin(2x-1)</p>
<p>ugh. . I thought I would did better than last time until I read this. I left 50 blank because I didn’t want to take the time to solve it and forgot how to use matrices in the calculator. I most likely got X^2<4 wrong. . . I put (0,2) (was it exclusive)? I didn’t see -q, i put positive q. I also got the number of lines perpendicular in xyz plane one wrong. So, one blank and three wrong could still get me an 800 if there are no other ones i got wrong, but in october I was in a similar situation and I ended up with a 750. . .</p>
<p>Answers i got to some controversial problems:</p>
<p>Standard deviation stays the same
the missing frequency value was 3
frequency of the sin/cos graph was 1/pi</p>
<p>Oh… crap.
I interpreted it as if they were asking for the mean of the data? The mean of the frequency makes less sense…</p>
<p>@ olleger</p>
<p>for the 0<x<pi/2, if you plugged in a number such as 60 degrees for the second one, you would get 2sin(60)cos(60) = 0.866025</p>
<p>so it’s just I and III.</p>
<p>Did anyone get the x^2<4 problem? Or am I just stupid?</p>
<p>None of the intervals seemed to satisfy the inequality.</p>
<p>^isn’t the frequency just how high it goes? in which case it would be pi b/c i got the answer by graphing it since i wasn’t sure</p>
<p>edit- reply to post about 3 or 4 up</p>
<p>@olleger</p>
<p>You’re right. My bad.</p>
<p>@ahage16
I’m pretty sure it was (0,2), because it makes total sense (at least to me…)</p>
<p>@ahage it was exclusive making it work. I put that too hence my tentative -3/-4… i do understand how it could be (-3,3)… It did say <em>included</em>… idk i just assumed it couldn’t be that because anything higher than 2 or lower than -2 wouldn’t have worked.</p>
<p>For the frequencies question, you had to multiply each of the values by it’s frequencies and divide by the sum of the frequencies. I got 4 as an answer after testing each of them.</p>
<p>@shadow, what am I right about? The cos sine stuff?
And mrdoodle it said a value of x not every value… plug in pi/4 and in radians…</p>
<p>agreed with ^nyem</p>
<p>The x^2 < 4 question totally sucked… I think I’m going to dispute it with collegeboard. (-2,2) should have definitely been one of the answer choices…</p>
<p>I got the frequency as 1/2pi lol ■■■. Also, I put 1-q for the circle question. -2… hope it stays like that.</p>
<p>For x^2<4, it would be (-2,2). However, they said which of THESE intervals satisfies the inequality?</p>
<p>Dang, 4 omits and 3 wrong… I really need to STOP reading this thread for the sake of my own sanity.</p>
<p>which Q was the X^2 <4 question I am pretty sure i didnt even come across it?lolol</p>
<p>@NYEM huh? so 1(2) + 2(1) + 3(1) + 4(1)…? thats 11…</p>
<p>I am still leaning towards my (-3,3)… anyone want to refute this? I know that 3^2 >4 lol but it said “which interval includes the solutions…” that’s why I changed my answer from your (0,2), which loses half of the solution.</p>
<p>@ Shadow</p>
<p>I don’t remember the exact wording, but i am pretty sure that it said which set contains all x values that satisfy the solution, so if (-3,3) was an answer, that would be right</p>