Determine the total area under the standard normal curve in parts (a) through (c) below. .. . (a) Find the area under the normal curve to the left of z = - 1 plus the area under the normal curve to the right of z = 1. The combined area is 0.3173 . (Round to four decimal places as needed.) (b) Find the area under the normal curve to the left of z = - 1.56 plus the area under the normal curve to the right of z = 2.56. The combined area is (Round to four decimal places as needed.)The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. (a) What is the probability that a randomly selected bag contains between 1000 and 1400 chocolate chips, inclusive? (b) What is the probability that a randomly selected bag contains fewer than 1000 chocolate chips? (c) What proportion of bags contains more than 1200 chocolate chips? (d) What is the percentile rank of a bag that contains 1000 chocolate chips? . . . (a) The probability that a randomly selected bag contains between 1000 and 1400 chocolate chips, inclusive, is (Round to four decimal places as needed.)The mean incubation time of fertilized eggs is 19 days. Suppose the incubation times are approximately normally distributed with a standard deviation of 1 day. (a) Determine the 14th percentile for incubation times. (b) Determine the incubation times that make up the middle 39% of fertilized eggs. . . . (a) The 14th percentile for incubation times is days. (Round to the nearest whole number as needed.)