Let's call our estimate x. It will be the average of n IQ scores. Our average won't usually exactly equal the mean 97. But if we repeated averages over different sets of tests, the mean of our estimate the average would be the same as the mean of a single test,
μ = 97
Variances add, so the standard deviations add in quadrature, like the Pythagorean Theorem in n dimensions. This means the standard deviation of the average x is
σ = 17/√n
We want to be 95% certain
97 - 5 ≤ x ≤ 97 + 5
By the 68-95-99.7 rule, 95% certain means within two standard deviations. That means we're 95% sure that
μ - 2σ ≤ x ≤ μ + 2σ
Comparing to what we want, that's means we have to solve
2σ = 5
2 (17/√n) = 5
√n = 2 (17/5)
n = (34/5)² = 46.24
We better round up.
Answer: We need a sample size of 47 to be 95% certain of being within 5 points of the mean
Answer:
B
Step-by-step explanation:
supplementary angles =180 degrees
180-117=63
Answer:
$20
Step-by-step explanation:
50% of Fundraising goal= 0.5 x $40
= $20
The best answer to the question that is being stated above would be that A and B are both dependent. If I was told that P(A | B) = P (B | A), then the true statement is that both variables inside would be dependent upon each other, no matter if you exchange their places with one another.
So you divide 22. 44 by 6 it will be 3.74 . See image for steps
