Find the probability of the indicated result Use the normal

Find the probability of the indicated result. Use the normal curve approximation to the binomial distribution. A battery company has found that the defective rate of its batteries is 0.03. Each day, 400 batteries are randomly tested. On Tuesday, 14 are found to be defective

Solution

mean = number of batteries * defective rate = 400 * .03

mean = 12

standard deviation = square root ( mean * (1-0.03))

standard deviation = 3.412

calculating normal distribution between two values 13.5 , 14.5

we get probability = 0.097