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
One hundred and three million, seven hundred and twenty-seven thousand, four hundred and ninety five.
Use a variable to represent the number of hours the technician will work, plus the $50.
50+25x
This would be the expression used to find the amount of money the technician needs.
Step by step guide
1)carry the chicken over and put it there
2) farmer cross alone to carry the corn over and carry the chicken back
3) put the chicken there and carry the fox to put there with th3 corn
4) go back to get the chicken
I believe it is 180° around H and translate 2 up 5 right
