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%
The answer is $57.73 because you multiply 50.2 and .15 to get the tax. Then, you add the tax, which is $7.53. You add 7.53 and 50.20 to get the answer.
Answer:
A function is a relation in which each possible input value leads to exactly one output value
Answer:
482.5 ft^2.
Step-by-step explanation:
The figure can be regarded as a rectangle with a triangle cut out of one corner.
The base of the triangle = 25-20 = 5 in and the height = 20 - 13 = 7 in.
The required area = area of rectangle - area of triangle
= 25*20 - 1/2 * 5 * 7
= 500 - 17.5
= 482.5 ft^2
Answer:
The stands will change color at the same time after 54 seconds.
Step-by-step explanation:
Find the Lcm number of both number (18 and 27)
The answer will be 54