<span>Last
year, the average math SAT score for students at one school was 475. The
headmaster then introduced a new teaching method hoping to improve scores. This
year, the mean math SAT score for a sample of students was 491. The headmaster
concluded that the new teaching method produces higher SAT scores. The problem
with reporting results this way is voluntary response. The information of how
the teaching method isnot mentioned.</span>
Answer:
73.6
61.824
.2776
2.3
1.342
.4129
*note* I had trouble reading the standard deviation of the second part, so if it's not 3 then leave a comment and i will fix it*
Step-by-step explanation:
1.)
the mean would be something like 460*.16= 73.6
The variance should be 460*.16(1-.16)= 61.824 which means the standard deviation is √61.824= 7.863
for p to be less than .15 it would have to be less than .15*460= 69
(69-73.6)/7.863= -.59 which has a probability of .2776
2.)
the mean is 2.3
I am not sure if the standard deviation is 3 or .3 (picture is kind of blurry)
I am thinking that it's three which would mean that the standard deviation would be √(3²*(1/5))= 1.342
(2-2.3)/1.342= -.22 = .4129
Answer:
x = 2 and y = 3
Step-by-step explanation:
We have
x+2y = 8 -----equation (i)
2x-y = 1 -----equation (ii)
Now,
x+2y = 8
or, x = 8-2y ------equation (iii)
Again,
2x-y = 1
or, 2x = 1+y
or, 2x-1 = y
Putting the value of 'x' from equation (iii)
or, 2(8-2y)-1 = y
or, 16-4y-1 = y
or, 16-1 = y+4y
or, 15 = 5y
or, y = 15/5
or, y = 3
Putting the value of 'y' in equation (iii)
x = 8-2y
or, x = 8-(2×3)
or, x = 8-6
or, x = 2
Therefore, x = 2 and y = 3.
c^2 = a^2 + b^2 - 2(ab)(cos C)
c^2 + 2(ab)(cos C) = a^2 + b^2
2(ab)(cos C) = a^2 + b^2 - c^2
cos C = (a^2 + b^2 - c^2) / 2ab - Answer choice E
Hope this helps! :)
Answer:
5000+500+10+3=5500+13=5513
Step-by-step explanation:
