Answer:
r = 2.39 and C=2πr=2·π·2.39≈14.99997
Step-by-step explanation:
Using the formula
C=2πr
Solving for r=C 2π=15
2·π≈2.38732
and then u round up the 7 told the 8 to go up.
2.39
12,089 is less than 12,098
The first choice is the correct one.
Answer:
1st
Step-by-step explanation:
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:
27000 inches^3
Step-by-step explanation:
The volume of a cube is sidelength^3.
The side length is 30 inches, so the volume is 30^3 = 27000 inches^3.
