21. The scores on a certain test follows a normal distribution with mean 70 and standard deviation 5. What is the probability that a student will receive a score between 75 and 85?4

22. The American Red Cross says that about 11% of the U.S. population has Type B blood. A blood drive is being held at your school. What is the probability thatexactly 2of the first 20 blood donors have Type B blood?3

23. According to the IRS, the average length of time for an individual to complete an IRS Form 1040 is 10.53 hours and the standard deviation of 2 hours. What is the probability that 36 taxpayers if randomly selected finished their Form 1040s in an average of less than 12 hours?3

24. Assume the following probabilities for two events, and :3

() = 0.50, () = 0.70, ( ) = 0.85

Are the events, and , independent in this situation?