Each of 12 refrigerators of a certain type have been returned to a distributor because of the presence of a high pitched oscillating noise when the fridge is running. suppose that 5 of these 12 have defective compressors and the other 7 have less serious problems. if they are examined in a random order, let x= the number among the first 6 examined that have a defective compressor. compute the following

a) p(x=5)

b) the probability that x exceeds its mean by more than 1 standard deviation