According to the US Bureau of Labor and Statistics, in 2010, the average America
ID: 2935263 • Letter: A
Question
According to the US Bureau of Labor and Statistics, in 2010, the average American family spent $124 per week on groceries. Suppose grocery expenditure is normally distributed and suppose the standard deviation was $25. If one randomly selected family's grocery expenditure falls in the bottom 33% of all families, at most what did they spend?
Suppose that there are an average of 8 flaws in 20 yards of fabric. What is the probability that you will find your first flaw within 2 yards?
Explanation / Answer
7) for 33 percentile ; z =-0.44
hence corresponding value =mean +z*std deviation=124-0.44*25=113
option A is correct
8)
mean distance between 2 flaws =20/8=2.5 yards
hence probability of flaw with in 2 yards =P(X<2)=1-e-2/2.5 =1-e-0.8 =1-0.4493 =0.5507
option D is correct
9)
as probability of a point in a continuous distribution is equal to 0 cause area under a point on a curve is 0,
hence option A is correct
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