Can someone please tell me how they solve this problem step by step. I don't understand how this person got the numbers 165-170/8.94. I have no clue how they randomly came up with these numbers. I'm in tears over this I need to get over a 70 in order to pass this class and secure my spot for nursing school this fall. Please break it down as simply as possible. This is my worst subject and I am taking this course online with no lecture or help whatsoever.

Suppose that in a large hospital system, that the average (mean) time that it takes for a nurse to take the temperature and blood pressure of a patient is 150 seconds with a standard deviation of 35 seconds. What is the probability that 30 nurses selected at random will have a mean time of 155 seconds or less to take the temperature and blood pressure of a patient? Your Answer: a. H .. E Z _ 0x xbar = 155 xbar u = 155 150 = ' We calculate the standard deviation of the sample distribution: a 35 639 r=== . ' J3 m Calculate the z-score: ' 65 17 x P = 10 = -.56 a, 8.9+ So, we want to nd P(Z