In a study of exhaust emissions from school buses, the pollution intake by passengers was determined for a sample of nine school buses used in the Southern California Air Basin. The pollution intake is the amount of exhaust emissions, in grams per person per million grams emitted, that would be inhaled while traveling on the bus during its usual 18-mile18-mile trip on congested freeways from South Central LA to a magnet school in West LA. (In comparison, a city of 11 million people will inhale a total of about 1212 grams of exhaust per million grams emitted.) The amounts for the nine buses when driven with the windows open are given in the table. 1.15 0.33 0.40 0.33 1.35 0.38 0.25 0.40 0.35   A good way to judge the effect of outliers is to do your analysis twice, once with the outliers and a second time without them. Give the 90%90% confidence interval with all the data for the mean pollution intake among all school buses used in the Southern California Air Basin that travel the route investigated in the study. Give your answers to three decimal places. What is  lower bound     upper bound   Give the 90%90% confidence interval with the outliers removed for the mean pollution intake among all school buses used in the Southern California Air Basin that travel the route investigated in the study. Note that the outliers are 1.15 and 1.35.. Give your answers to three decimal places. lower bound outliers removed:   upper bound outliers removed:

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...