Question 153094
Recently the national average yield on municipal bonds has been u=4.19%. A random sample of 16 Arizona municipal bonds gave an average yield of 5.11% with a sample standard deviation s= 1.15%. does this indicate that the population mean yield for all Arizona municipal bonds is greater than the national average? Us a= 0.05. Assume x is normally distributed.
--------------------- 
a) state the null and alternate hypothesis.
Ho: u = 4.19
Ha: u > 4.19
--------------------- 
b) identify the sampling distribution to be used. the standard normal
 distribution or the student's T distribution. find the critical value (s).
Ans: T-distribution with df= 15;
critical value = 1.753
--------------------- 
c) compute the z or t value of the sample test statistic.
t(5.11) = (5.11-4.19)/[1.15/sqrt(16)] = 3.2
---------------------  
d) find the P value or an interval containing the P value for the sample test statistic.
P(3.2 < t < 100) with df=15 = 0.002982...
------------------------------------------- 
e) Based on your answers to A through D, decide whether or not to reject the null hypothesis at the ficen significance level. Explain your conclusion in the context of the problem. 
Ans: Since the p-value is less than 5% and less than 1% we reject Ho.
The national average yield on municipal bonds is greater than 4.19% 
=========================
Cheers,
Stan H.