<p>Any one put “Only III” for the change in standard deviation.</p>
<p>The questions was something to the effect of…
Which of the following would change the standard deviation of a set of numbers?
I. Add 5 to all numbers
II. Subtract 5 to all numbers
III. Multiply 5 to all numbers</p>
<p>@ voodoo:</p>
<p>The answer was 1/4. The only way yo get an odd product is and odd number multiplied by an odd number. 1/2 of the numbers are odd in each set so .5 x .5 = 0.25</p>
<p>The three answer choices from the central tendency was II only (median = mean)</p>
<p>For the f inverse problem, you had to find the inverse of f inverse (meaning just f) and then set it equal to 5 and solve for x.</p>
<p>The matrix was 0. I did it on the calculator.</p>
<p>The odd sum probability was 1/4 (1/2 * 1/2)</p>
<p>The vector was in the fourth quadrant. b - a (or was it a - b?) just means b + (-a). I drew -a and saw the vector difference as the diagonal of a parallelogram having sides -a and b.</p>
<p>^ o DAMN!!! lol i should of though of it that way (i took like 2sec to do that question cuz i thought it was obvious…but apparently not :(). Ok now i have officially 2 skips and 5 wrong (raw score of 42ish) out of the 30-35 questions i talked about. $%#& i missed the 800 mark (unless the curve is EXTREMELY good) and i probably got a few others wrong too :/</p>
<p>I am hoping that this curve is a little more generous that usual because apparently the majority thought it was hard as well.</p>
<p>for those of you who have taken this test before, was this test harder or easier than that and how do you predict the curve will be?</p>
<p>Aww crap. I messed up on the odd number question, I thought it said even so I got 1/2 instead of 1/4. And, I graphed the limit one on my calc and there didn’t appear to be any limit, I guess I didn’t put in the equation properly or something.</p>
<p>Does anyone remember the one about surface area of the prism? I kept getting whole numbers when all of the answer choices were decimals. What did you guys put? (Sorry if this has already been talked about, I didn’t read the whole thread.)</p>
<p>I was feeling really good coming out of this test, but reading this thread has got me down. =(</p>
<p>could some on post like a total compilation instead of bits???</p>
<p>If you thought it said even you’d still be wrong as the answer would be 3/4.</p>
<p>Which of the following would change the standard deviation of a set of numbers?
I. Add 5 to all numbers
II. Subtract 5 to all numbers
III. Multiply 5 to all numbers</p>
<p>I put None…Im not sure if I’m right but if you were to increase or decrease all the increments by the same value, I dont think the deviation can change?</p>
<p>I took the Jan. test and got a 770.
I thought this test was easier. I had like 10 omits on the Jan. exam.</p>
<p>This one I’m thinking 2 wrong & 3 omits. Anyone know what that would be.</p>
<p>@ ZorroX99: I thought it was III only</p>
<p>^ >< 3 omits and 2 wrong is like a 44-45 raw score for 800. GODDAMNIT!! y such a harsh curve!!!</p>
<p>Um, I want to go back to the vector problem. Think about it. If two lines hit in the thied quadrant, how can the resultant line be in the 3rd quadrant?
So, isn’t the asnwer 3rd quadrant?</p>
<p>Why did everyone get the asnwer in the fourth quadrant?</p>
<p>Yes, it is III only.</p>
<p>Take any set of numbers = Call it set A. Then create three other sets where you impose treatment.
The one with multiplication has a different std.</p>
<p>Im in AP Stats. So I know what I’m doing here.</p>
<p>yeah it was def III. and for the vector one you just had to subtract x and y values to find out where the new point would be</p>
<p>what do you mean? The only values there were a and b . . .</p>
<p>well i just estimated the values of each point.</p>
<p>Ashwin,</p>
<p>For the vectors, b-a, one approach you can take, is to add b + (-a). You take a, then flip it so that the arrow is on the other side - that’s (-a). Then, slide that vector’s endpoint to the end of vector b (the arrow) and that shows you b + (-a). Then, connect b’s vertex to (-a)'s arrow - that’s in quadrant IV.</p>
<p>EDIT: On second thought, the problem may have been a-b, I can’t remember. Either way, this type of technique works, like jamesford says.</p>
<p>I checked the standard deviation with a calculator. It is III.</p>
<p>About the vector one: Both vectors were in the first quadrant pointing northeast. The question asked a - b. That is the same thing as a + (-b). To find a negative vector, all you have to do is “flip” it so it is pointing in the opposite direction. Hence, it is in the 3rd quadrant. Now you can find a + (-b). The two vectors have the same starting point, one pointing SW and the other NE. Because the vectors have the same initial point (as opposed to one vector “running into” the other), the vector sum is the diagonal of the parallelogram whose sides are the two vectors. It’s in the 4th quad.</p>