Q1. A total 225 people were asked to report their hourly wages. The mean of the sample was 28 and it is known that the population standard deviation is 12
a) Find the 95% confidence interval for the mean.
b) Find the 90% confidence interval for the mean.
Q2. Define each of the following:
a) Population
b) Simple random sample of size n.
Q3. The probability a child is born with type O blood is 25%. If there are 8 children in a pre-school classroom
a) What is the probability exactly 2 have type O blood?
b) What is the probability at most 2 have type O blood?
Q4. Find the 82% Confidence interval if the sample mean is 10, n = 36 and the population standard deviation is 18.
Q5. Suppose p =- .6 and n = 1000. Use the normal approximation to find
a) P(X ≥ 580)
b) P(620 ≤ X ≤ 630)
c) What value of X is the cut-off for the bottom 5%.