9;9
Explanation:
You divide 18 by 2 to get 9 and divide 27 by 3 to get 9.
Hope that helps!
You can complete this by solving:
Which should give you .274418 or 27.44%
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
Triangle APQ is the image of ABC under a dilation centered at vertex A with scale factor ½. Triangle RBT is the image of ABC under a dilation centered at vertex B with scale factor ¾ . Which statement about ABC , APQ , and RBT is correct? none of the triangle are similar
All three triangles are similar
Triangle APQ an RBT are not similar
