I need help I keep getting the answer wrong and i dont know what am i doing on some you use R studio

15. Let X be a random variable with Normal distribution, mean = 12, sd = 2. Find the value of x such that P(X > x) = 0.05. a) 1.645 b) 1.645 c) 0.520 d) 15.290 e) 8.710

9. An SRS of 25 students at UH gave an average height of 6.2 feet and a standard deviation of .1 feet. Construct a 90% confidence interval for the mean height of students at UH. a) (6.166, 6.234) b) (6.029, 6.371) c) (4.950, 7.650) d) (4.700, 8.000) e) (6.193, 6.207)

5. Suppose that x is normally distributed with a mean of 50 and a standard deviation of 10. What is P(x 74.50)? a) 0.493 b) 0.995 c) 0.007 d) 0.993e) 0.496

4. Costs for standard veterinary services at a local animal hospital follow a Normal distribution with a mean of $89 and a standard deviation of $23. What is the probability that one bill for veterinary services costs less than $45? a) 0.5000 b) 0.9721 c) 0.0139 d) 0.0279 e) 0.9861

3. Suppose the time a child spends waiting at for the bus as a school bus stop is exponentially distributed with mean 6 minutes. Determine the probability that the child must wait at least 9 minutes on the bus on a given morning. a) 0.4231 b) 0.5231 c) 0.2231 d) 0.4463 e) 0.2769