Customers arrive at the movie theater at the movie time indicated only to find they need to sit through commercials and previews. Many complain that this time is too long. WSJ 2012
determined in a preliminary sample that the standard deviation of the amount of time devoted to
previews is 4 minutes. If we want to estimate the population mean time for previews at movie
theatres with a margin of error of 75 seconds, what sample size should be drawn?
b. Assume a 99% confidence level

answer   download the app called socratic on your phoner:

step-by-step explanation:

answer is x<

geometry: triangles

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call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

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