Question

Suppose the distribution of weekly study times amoung Rutgers students has mean 20 hours and standard...

Suppose the distribution of weekly study times amoung Rutgers students has mean 20 hours and standard deviation 8 hours.

1. In a sample size of 75, determine the probability that the average study time is more than 18.5 hours. Write your answer as a decimal with 3 digits.

Homework Answers

Answer #1

Solution :

Given that ,

mean = = 20

standard deviation = = 8

n = 75

= 20

= / n =8 / 75 = 0.9238

P( >18.5 ) = 1 - P( < 18.5)

= 1 - P[( - ) / < (18.5 -20) /0.9238 ]

= 1 - P(z <-1.62 )

Using z table

= 1 - 0.0526

= 0.9474

probability= 0.947

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