The mean of 10 randomly selected students is definitely more likely to be closer to 75. 10 randomly selected students to include information and are more like to reflect the class’s scores. Consider an extreme example. Seventy-five students in a class of 100 earned perfect scores. The other 25 earned zeros. The average score of the class would be 75. A sample of 10 random students would almost certainly include more 100s then 0s, but both would be included in the sample. The mean of this samples score is closer to 75 than any individuals.
This is the concept of algebra, to solve the expression we proceed as follows;
cos 2x-cosx=0
cos 2x=cosx
but:
cos 2x+1=2(cos^2x)
thereore;
from:
cos 2x=cos x
adding 1 on both sides we get:
cos 2x+1=cos x+1
2(cos^2x)=cosx+1
suppose;
cos x=a
thus;
2a^2=a+1
a^2-1/2a-1/2=0
solving the above quadratic we get:
a=-0.5 and a=1
when a=-0.5
cosx=-0.5
x=120=2/3π
when x=1
cos x=1
x=0
the answer is:
x=0 or x=2/3π
The quantity you want is the area under the standard normal curve (with mean 100 and std dev 15) between 110 and 120.
According to my TI-83 calculator,
normalcdf(110,120, 100, 15) = 0.16, or 16%.
Uhhh... I think it’s D but that could be wrong
f(x) = x² + 5x - 2
f(x) + 2 = x² + 5x - 2 + 2
f(x) + 2 = x² + 5x
f(x) + 2 = x(x) + x(5)
f(x) + 2 = x(x + 5)
f(x) = x(x + 5) - 2
(h, k) = (-5, 2)
