Two more probability problems. Husband in hospital, helping him out. Thanks!?

2. There are 20 questions in a multiple choice test. Each question has five choices and one correct answer out of these five choices. A student did not study. He answers the questiosn at random. What are the probabilities that he makes:


a. more than 10 answers right


b. exactly 8 right


c. at most, 7 right











3. A can company reports that the number of machine breakdowns in an 8 hour shift has a mean of 1.5. Find the probability that there will be:


a. exactly 2 breakdowns


b. fewer than 2 breakdowns


c. no breakdowns in 3 consecutive shifts

Two more probability problems. Husband in hospital, helping him out. Thanks!?
The irony of question #2 is staggering. I can only hope it's a joke. Otherwise it is going to become a self-fulfilling prophecy.
Reply:Well, I am not going to get out my calculator for this, so. . .





I would have to use a graphing calculator, though, to carry out the commands. .


2a) 1-binomialcdf(20 .2, 9)


2b) binomialpdf(20, .2, 8)


2c) binomialcdf (20, .2, 7)





3) Wouldn't I have to know how many machines there are?
Reply:This doesn't make sense. Is your husband still in college or something? Or even in high school still? Also, if he were in the hospital, wouldn't his teacher lay off on the homework??? Or is this your homework?

quince