A random sample of size 36 is taken from a population having mean 20 and variance...

A random sample of size 36 is taken from a population having mean 20 and variance 9.What is the probability that the sample meanXwill be at least 21?

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Expert Solution

Solution :

Given that,

mean = = 20

variance=9

standard deviation = = 9=3

n=36

= =20

= / n = 3 / 36 = 0.5

P( > 21) = 1 - P( <21 )

= 1 - P[( - ) / < (21-20) /0.5 ]

= 1 - P(z <2 )

Using z table

= 1 - 0.9772

= 0.0228

probability= 0.0228

orchestra answered 1 year ago

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