Let the sample mean of a distribution of 36 persons is 10 and standard deviation is 4. Find a 95% confidence interval of the population mean. Select one: O a. [8.69, 11.31] O b. [9.04, 11.96] O c. [8.04, 10.96] O d. [9, 11] If A and B are mutually exclusive events such that P(A )=0.7 and P(B)=0.2 then P(A U B) Select one: O a. 0.9 O b. 0 O c. 0.5 O d. 0.8