Researchers are interested in the mean age of a certain population. A random sample of 10
individuals drawn from the population of interest has a mean of 27. Assuming that the population is
approximately normally distributed with variance 20,can we conclude that the mean is different
from 30 years ? (α=0.05). If the p-value is 0.0340 how can we use it in making a decision?
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n=10Xbar=27population sd = sqrt(20)Ho: mu = 30Ha: mu=/=30Z= (Xbar-mu)/(sd/sqrt(n))=(27-30)/(sqrt(20)/sqrt(10))=-2.12Calculating p value form the z table at z=-2.12we get p value as 0.017but it is a two tail test and hence we get p value=2*0.0170 =0.0340As we know that the p value is less than 0.05 we can reject thenull hypothesisHence we conclude that the mean is different from 30yearsHope the above answer has helped you in understanding theproblem. Please upvote the ans if it has reallyhelped you. Good Luck!! ...