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Group Exercise: Z-test

Calculate the Z-test and determine the probability of the following outcomes. The mean occupational prestige score in Kings County in 2013 is 44.8. The population standard deviation is 18.3. Each group will demonstrate their work on the whiteboard.

You can compute the area under the normal curve here: http://www.stat.berkeley.edu/~stark/SticiGui/Text/clt.htm#normal_curve

1. What is the probability of drawing a sample of 800 working adults from Kings County with a sample mean of 45 or more?
2. What is the probability of drawing a sample of 1000 working adults from Kings County with a sample mean below 43?
3. What is the probability of drawing a sample of 500 working adults from Kings County with a sample mean between 42.5 and 44.5?
4. What is the probability of drawing a sample of 1200 working adults from Kings County with a sample mean between 44 and 45?
5. What is the probability of drawing a sample of 900 working adults from Kings County with a sample mean between 44.8 and 46?

Comments

z=-2.812
z=-0.367
P=35.43%

The probability of drawing a sample of 1000 working adults from Kings Country with a sample mean below 43 is .07%

The probability of drawing a sample of 800 working adults from Kings County with a sample mean of 45 or more is 37.73%

standard deviation of sample population - 18.3/(35.6)
[1] 0.5140449
z test =
> (44-44.8)/0.51
[1] -1.568627
> (45-44.8)/0.51
[1] 0.3921569
probability = 59.31%