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:

Step-by-step explanation:
The point-slope form of an equation of a line:

<em>m</em><em> - slope</em>
<em>(x₁, y₁)</em><em> - point on a line</em>
<em />
We have

Substitute:

Answer:
326
Step-by-step explanation:
Given: Microscopes. Each one costs $200 and resells online for $526.
To find: What is the mark-up percentage?
Solution: Simply take the sales price minus the unit cost, and divide that number by the unit cost. Then, multiply by 100 to determine the markup percentage.

Net Profit Margin = 61.98%
Net Profit = $326.00
Profit Percentage = 163.00%
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