Respuesta :
This problem represents "binomial probability," because any given "experiment"Â can have only two possible outcomes: Â defective or not defective.
Here the "population" probability that a given microwave unit is defective is 0.015. Â We arbitrarily define "defective microwave" as a "success" and "non-defective microwave" as a "failure."
We can obtain binomial probability values from a calculator such as the TI-83, from a table or from the binomial probabilty formula. Â In all of these cases the number of samples is given and is n=20; the probability of "success" is also given and is p=0.015.
Case 1: Â What is the probability that exactly 1 microwave unit is defective?
Using the TI-83: Â Â binompdf(20,0.015,1) = 0.225, or 9/40. Â
Case 2: Â What is the p. that at most 2 are defective? Â Add together the binomial probabilities binompdf(20,0.015,0),binompdf(20,0.015,1),binompdf(20,0.015,2).
Result: Â 0.7391 + 0.2250 + 0.0326 = 0.9967.
Mean: Â The mean of a binomial probability such as this one is simply np, which in his case is 20(0.015)=0.30. Â Find and apply the formula for the standard deviation.
Here the "population" probability that a given microwave unit is defective is 0.015. Â We arbitrarily define "defective microwave" as a "success" and "non-defective microwave" as a "failure."
We can obtain binomial probability values from a calculator such as the TI-83, from a table or from the binomial probabilty formula. Â In all of these cases the number of samples is given and is n=20; the probability of "success" is also given and is p=0.015.
Case 1: Â What is the probability that exactly 1 microwave unit is defective?
Using the TI-83: Â Â binompdf(20,0.015,1) = 0.225, or 9/40. Â
Case 2: Â What is the p. that at most 2 are defective? Â Add together the binomial probabilities binompdf(20,0.015,0),binompdf(20,0.015,1),binompdf(20,0.015,2).
Result: Â 0.7391 + 0.2250 + 0.0326 = 0.9967.
Mean: Â The mean of a binomial probability such as this one is simply np, which in his case is 20(0.015)=0.30. Â Find and apply the formula for the standard deviation.