SOLUTION: The number of minutes per week that students spend surfing the internet is normally distributed with a mean of 490 minutes and standard deviation of 53 minutes. Calc

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Question 847124: The number of minutes per week that students spend surfing the internet is normally distributed
with a mean of 490 minutes and standard deviation of 53 minutes.
Calculate the probability that the time, in a week, a student spends surfing the internet is
Given that 67% of students spend less than M minutes,
calculate the value of M, correct to 1 decimal place.

Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
X ~ Normal(490,53)
P[X < M] = .67
P[Z < (M-490)/53 ] = .67
(M-490) /53 = .44 (using z-table to find the z-score that gives .67)

M-490 = 23.32
M = 513.3