a simple random sample of size 36 is taken from a normal population with mean 20 and standard deivation of 15. What is the probability the sample,neab,xbar based on these 36 observations will be within 4 units of the population mean. round to the hundreths place
Solution :
_{} = / n = 15 / 36 = 2.5
= P[ -4 / 2.5 < ( - _{}) / _{} < 4 / 2.5)]
= P(-1.6 < Z < 1.6)
= P(Z < 1.6) - P(Z < -1.6)
= 0.8904
Probability = 0.8904
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