Answer:
Mean is 81%
standard deviation is approximately 4.2%
Step-by-step explanation:
Since the number of boys equals the number of girls, but it is not given, we name it "N". and proceed to calculate the mean as:
Mean = (0.78 * N + 0.84 * N) /(2 N)
using that the total number of students must be N boys + N girls = 2 N
Then the Mean becomes: N *(0.78 + 0.84) /(2 N) = (0.78 + 0.84) / 2 = 1.62 / 2 = 0.81
So the mean is 81%
Now, standard deviation will be calculated by first adding the squares of the deviations: (X-0.81)^2 for the N boys and for the N girls, and then finding the square root of this and finally dividing by the square root of N. That is:

Now finding the square root of this value, and finally dividing it by the square root of N:

which in percent form is: approximately 4.2%
Answer:
The answer is (d) ⇒ cscx = √3
Step-by-step explanation:
∵ sinx + (cotx)(cosx) = √3
∵ sinx + (cosx/sinx)(cosx) = √3
∴ sinx + cos²x/sinx = √3
∵ cos²x = 1 - sin²x
∴ sinx + (1 - sin²x)/sinx = √3 ⇒ make L.C.M
∴ (sin²x + 1 - sin²x)/sinx = √3
∴ 1/sinx = √3
∵ 1/sinx = cscx
∴ cscx = √3
Answer:
A. up
Step-by-step explanation:
Adding a value to the y-coordinate of a point shifts the point up by that amount.
Answer:
I'm confused. Is there more to the question?