<span>A medical researcher wants to investigate the amount of time it takes for patients' headache pain to be relieved after taking a new prescription painkiller. She plans to use statistical methods to estimate the mean of the population of relief times. She believes that the population is normally distributed with a standard deviation of 18 minutes. How large a sample should she take to estimate the mean time to within 4 minutes with 97% confidence?
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n = [z*s/E]^2
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n = [2.17*18/4]^2 = 96 when rounded up
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You can use the distance formula.
The distance formula says the distance between two given points (x1, y1) and (x2, y2)
=

Your given points are (8, -1) and (-2, -1).
The distance will be

.
But you could have recognized that both points have the same y-coordinate of -1, which means change in distance is determined by change in x-coordinates only.
Change in x-coordinates is |-8 - 2| = 10. There is absolute value because distance cannot be negative.
Answer:
Answer: $30.80
Step-by-step explanation: