The amount of pollutants that are found in waterways near large cities is normally distributed with mean 9.4 ppm and standard deviation 1.5 ppm. 40 randomly selected large cities are studied. Round all answers to 4 decimal places where possible. a. What is the probability that one randomly selected city's waterway will have more than 9.7 ppm pollutants? b. For the 40 cities, find the probability that the average amount of pollutants is more than 9.7 ppm. c. For part b, is the assumption that the distribution is normal necessary? O YesO No d. Find the IQR for the average of 40 cities. Round to two decimal places. Q1 - ppm Q3 - ppm IQR: ppm

Suppose that the distance of fly balls hit to the outfield (in baseball) is normally distributed with a mean of 254 feet and a standard deviation of 43 feet. Use your graphing calculator to answer the following questions. Write your answers in percent form. Round your answers to the nearest tenth of a percent. a) If one fly ball is randomly chosen from this distribution, what is the probability that this ball traveled fewer than 204 feet? P(fewer than 204 feet) = % b) If one fly ball is randomly chosen from this distribution, what is the probability that this ball traveled more than 216 feet? P(more than 216 feet) =

A developmental psychologist is interested in studying how long babies gaze at a photograph of a human face. To test this question, she shows a picture to a sample of six babies and records the length of their gaze in seconds. The data are as follows: 12, 17, 18, 20, 20, 29. Calculate the mean, median, mode, range, variance and standard deviation for the sample.

JA researcher takes an SRS of 80 people who go golfing.The average to be u52 years old. It was also determined that the standard deviation of cac ot golfers was la What is the probability that the sample mean is kss. than 47 years old? age of all golferswas determined years.