In developing an interval estimate for a population mean, the population standard deviation was assumed to be 10. the interval estimate was 50.92 ± 3.5. if population standard deviation is 30, the interval estimate would be: a. 60.92 ± 2.14 b. 50.92 ±12.14 c. 101.84 ± 4.28 d. 50.92 ± 4.28

Can someone me out here number 4 plz

Using pert, adam munson was able to determine that the expected project completion time for the construction of a pleasure yacht is 21 months, and the project variance is 4. a) what is the probability that the project will be completed in 17 months? b) what is the probability that the project will be completed in 20 months? c) what is the probability that the project will be completed in 23 months? d) what is the probability that the project will be completed in 25 months? e) what is the due date that yields a 95% chance of completion?

What is the solution to the division problem below x3+x2-11x+4/x+4