A simple random sample of 100 men is chosen form a population with mean height 71 in and standard deviation 2.5 in. What is the probability that the average height of the men in the sample is less than 70.5in?

Answer :

Answer:

2.28%

Step-by-step explanation:

The z score is used to determine how many standard deviations that the raw score is above or below the mean. If the z score is positive then the raw score is above the mean and if it is negative then it is below the mean. It is given by:

[tex]z=\frac{x-\mu}{\sigma}\\ \\\mu = mean, \sigma=standard\ deviation,x=raw\ score\\\\For\ a\ sample\ n\\\\z=\frac{x-\mu}{\sigma/\sqrt{n} }\\\\For\ x<70.5\ in\\\\Given \ that\ n=100, \mu=71\ in, \sigma=2.5\ in\\\\z=\frac{70.5-71}{2.5/\sqrt{100} }=-2\\\\From\ normal\ distribution\ table, P(x<70.5)=P(z<-2)=0.0228=2.28\%[/tex]

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