A study found that consumers spend an average of $21 per week in cash without be
ID: 3330579 • Letter: A
Question
A study found that consumers spend an average of $21 per week in cash without being aware of where it goes. Assume that the amount of cash spent without being aware of where it goes is normally distributed and that the standard deviation is $6 . Complete parts (a) through (c). a. What is the probability that a randomly selected person will spend more than $25 ? P(Xgreater than $25)equalsnothing (Round to four decimal places as needed.) b. What is the probability that a randomly selected person will spend between $8 and $19 ? P($8 less thanXless than$19)equalsnothing (Round to four decimal places as needed.) c. Between what two values will the middle 95 % of the amounts of cash spent fall? The middle 95 % of the amounts of cash spent will fall between Xequals $nothing and Xequals $nothing . (Round to the nearest cent as needed.)
Explanation / Answer
a) P(X > 25)
= P(z > (25 - 21)/6)
= P(z > 0.67)
= 0.2525
b) P(8 < X < 19)
= P((8 - 21)/6 < z < (19 - 21)/6)
= P(-2.17 < z < -0.33)
= 0.3543
c) z scores corresponding to middle 95% area = -1.96, 1.96
Hence,
95% of the amount of cash spent falls between (21 - 1.96*6) and (21 + 1.96*6) i.e. 9.24 and 32.76
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