1 A normal distribution has a mean of 10 and a standard deviation of 2. What is the z score for x=13?

2. A normal distribution has a mean of 7.5 and a variance of 4. What is the z score for x=9?

3. A normal distribution has a mean equal to 3.4? What is the probability of a score above the mean?

4. A normal distribution has a mean equal to 4.6 and a standard deviation equal to 1.4. What score is that cutoff for the top 10% of this distribution?

5. A normal distribution has a mean equal to 10 and a standard deviation equal to 1. What is the z-score cutoff for the top and bottom 2.5% of this distribution? 6. Suppose we select a sample for a population of children in which an equal number of children live with or without their biological parents. We select a sample of 50 children. What is the probability that 30 children in this sample will be children who live with their biological parents? Hint: use the normal approximation to the binomial distribution, where p and q equal.50

7. Suppose that 10% of students earn an A in a statistic course. Using this percentage, what is the probability that exactly 25 students in a random sample of 200 students will earn an A in a statistics course?