11. Registered nurses in Pennsylvania earn an average hourly salary of $37.50 an hour. Assume these salaries are normally distributed with a standard deviation of $4.30. What is the probability that a randomly selected nurse earns less than $36.00 an hour? 12. Suppose we test whether a balanced coin lands on heads 50% of the time. We decide to collect samples of coin tosses, and we compare the percentage of times coins land on heads for different samples. What is the minimum sample size required to assume the sampling distribution of proportions will be normally distributed in this case? 13. Registered nurses in Pennsylvania earn an average hourly salary of $37.50 an hour. Assume these salaries are normally distributed with a standard deviation of $4.30. What is the probability that a randomly selected nurse earns $36.50 an hour? 15. If a random variable is not normally distributed, what is the minimum sample size required to assume the sampling distribution of the mean will be normally distributed? 16. If a random variable is not normally distributed, what is the minimum sample size required to assume the sampling distribution of the mean will be normally distributed? 17. Registered nurses in Pennsylvania earn an average hourly salary of $37.50 an hour. Assume these salaries are normally distributed with a standard deviation of $4.30. 2.5% of all salaries will be greater than what value? 18. 58% of registered nurses work in general medical and surgical hospitals. Assume a random sample of 20 registered nurses is selected. What is the probability that the sample proportion of registered nurses working in general medical and surgical hospitals is greater than .56