The ratio of 1/2 to 3 is equal to the ratio of 5 to what numberplz halp ;(
1 answer:
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Answer:
a) 6.68th percentile
b) 617.5 points
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
a) A student who scored 400 on the Math SAT was at the ______ th percentile of the score distribution.
has a pvalue of 0.0668
So this student is in the 6.68th percentile.
b) To be at the 75th percentile of the distribution, a student needed a score of about ______ points on the Math SAT.
He needs a score of X when Z has a pvalue of 0.75. So X when Z = 0.675.
Answer:
Step-by-step explanation:
They wanted to complete the square so they took the thing in front of x and divided by 2 then squared. Whatever you add in, you must take out.
Now we are read to write that one part (the first three terms together) as a square:
I don't see this but what happens if we find a common denominator for those 2 terms after the square. (b/2a)^2=b^2/4a^2 so we need to multiply that one fraction by 4a/4a.
They put it in ( )
I'm going to go ahead and combine those fractions now:
I'm going to factor out a -1 in the second term ( the one in the second ( ) ):
Now I'm going to add (b^2-4ac)/(4a^2) on both sides:
I'm going to square root both sides to rid of the square on the x+b/(2a) part:
Now subtract b/(2a) on both sides:
Combine the fractions (they have the same denominator):
<span>A(2, -2), B(4, -2), C(1, -3), D(5, -3).
A'(1, 2), B'(1, 4), C'(2, 1), D'(2, 5)
That looks like a rotation 90 degrees around the origin then a translation.
Let's do the rotation ABCD->A"B"C"D"
The rotation is (x,y)->(-y,x)
</span>A"(2, 2), B"(2,4), C"(3,1), D"(3,5).
Compare to
A'(1, 2), B'(1, 4), C'(2, 1), D'(2, 5)
we need to translate one unit to the left.
Answer: 90 degree rotation around the origin then translation by (-1,0)
A'(1, 2), B'(1, 4), C'(2, 1), D'(2, 5)
That looks like a rotation 90 degrees around the origin then a translation.
Let's do the rotation ABCD->A"B"C"D"
The rotation is (x,y)->(-y,x)
</span>A"(2, 2), B"(2,4), C"(3,1), D"(3,5).
Compare to
A'(1, 2), B'(1, 4), C'(2, 1), D'(2, 5)
we need to translate one unit to the left.
Answer: 90 degree rotation around the origin then translation by (-1,0)