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:
answer iss ( -2 , 0 )
Step-by-step explanation:
Revenue = Sales Volume (x) times Price. Price depends on volume sold: the more you are willing to sell per week, the lower your average price will have to be to get them all sold.
<span>eg, if there are a fixed number of buyers with a variety of incomes, then you might be able to sell the first 10 per month for £30 each through the up-market High Street jeweller. If you want to sell an extra 10 per month you might have to reduce the price to £15 and sell them through Asda/WalMart. And to move another 10 per month you may have to sell them from a street stall at £5 each! </span>
If 3z=2z+5 and z=5, then you’d just plug the 5 in.
3(5)=2(5)+5 —> 15=10+5 —> 15=15
This statement is TRUE because 15 does equal 15.
I hope this helps. :)
Hey there!
840 = 100%
x = 17%
840/x = 100%/17%
(840/x) * x = (100/17) * x 840 = <span>5.8823529411765
</span>
<span>= 840/5.8823529411765 = 142.80
The correct answer to your question is option C.
The tip Christian should leave is $142.80.
Hope this helps you.
Have a great day!
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