Question

In: Statistics and Probability

Suppose that a population is known to be normally distributed with µ = 317 and σ...

Suppose that a population is known to be normally distributed with µ = 317 and σ = 90. If a random sample of size n = 50 is selected, calculate the probability that the sample mean is greater than 300.

Solutions

Expert Solution

Solution :

Given that,

mean = = 317

standard deviation = = 90

= =317

= / n = 90 / 50 = 12.73

P( >300 ) = 1 - P( < 300)

= 1 - P[( - ) / < (300-317) /12.73 ]

= 1 - P(z <-1.34 )

Using z table

= 1 - 0.0901

=0.9099


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