I am using Excel to enter the formulas, please advise with what I am doing wrong

A. What is the probability of randomly selecting a value below 250, in a normal distribution with a mean of 200 and a standard deviation of 50?

I am using Excel: the formula that I was able to come up with is: =NORM.INV(250,200,50)

Is this right?

B. What is the probability of randomly selecting a value between 225and 300, in a normal distribution with a mean of 200 and a standard deviation of 50?

Excel formula: =NORM.INV(225, 200,50,TRUE)-NORM.INV(300,200,50)

C. What is the probability of randomly selecting a value between 160 and 200, in a normal distribution with a mean of 250 and a standard deviation of 80?

=NORM.INV(160,250,80)-NORM(200,250,80) d) What is the probability of randomly selecting a value above 325, in a normal distribution with a mean of 400 and a standard deviation of 50? e) A school obtained a grant to offer free tutoring to students at risk of failing a statistics class. The grant specifies that students who score within the lowest 20%, on a standardized statistics test, will receive free tutoring. Suppose a teacher wanted to find the actual score (i.e. the raw score), in a normal distribution, that marks the point at which students who score below that point will receive free tutoring. What would that score be, if the mean of the distribution was 80 and the standard deviation was 10? f) Suppose Mark is taken to the emergency room after a car wreck and the doctors think he might have a brain injury. They give him a finger-tapping-speed test that has a mean of 100 and a standard deviation of 10 in the normal population and they decide to use a one-tailed test with all 5% of alpha in the lower end of the distribution. That means that they will conclude that he has brain damage if his score is at or below the point in the distribution that marks the lower 5% of the distribution. Also, suppose that the doctors believe that they know that the mean of the alternative distribution is 90 with a standard deviation of 10. Use Excel to find the probability of making a Type II error in this scenario.