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%
cubic means 3 so there is a total o 3 roots
there is 1 real zero ( where the line crosses the x axis) the other 2 would be complex zeros
Answer is D
Answer:
hello governor
Step-by-step explanation:
The function given is,
a) Domain
This is the set of all points over which a function is defined.
Therefore, the domain of the function is
b) Solving for the value of a
To solve for the value of a, the value of y = 0 at x = a
Therefore,
Solving for a
Collect like terms
Divide both sides by 3
Hence,
Answer:
B) 47.5%
Step-by-step explanation:
Refer to the normal distribution chart attached. If 130 is 2 standard deviations higher than the mean (ignore the numbers beneath the percentages), then by the empirical rule, this means that 34%+13.5%=47.5% of adults are between IQs of 100 and 130. Therefore, option B is correct.
