Question

In: Statistics and Probability

For a normal population with = 60 and = 20, what is the SE, Z-score and...

For a normal population with = 60 and = 20, what is the SE, Z-score and the probability of obtaining a sample mean equal to or greater than 65 for a random sample of n = 100? Show your work for SE and Z-score calculations. 2 pts

Answer:

	Value	Work/Explanation
SE
Z score
P (X-bar ≥ 65)

Expert Solution

Solution :

Given that ,

mean = = 60

standard deviation = = 20

n = 100

= = 60

SE = = / n = 20/ 100 = 2

= 65

Using z-score formula,

z = - /

Z = 65 - 60 / 2

z = 5 / 2

z = 2.50

P( ≥ 65 ) = 1 - P( 65)

= 1 - P[( - ) / (65 - 60) / 2 ]

= 1 - P(z 2.50 )

Using z table,

= 1 - 0.9938

= 0.0062

orchestra answered 2 years ago

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