(a) Make a stemplot. Are there outliers or strong skewness that would forbid use of the i procedures? O The stemplot suggests the presence of outliers. The sample is small and the stemplot skewed, so the use of r not appropriate. procedures O The stemplot suggests the presence procedures is appropriate. O The stemplot does not indicate the presence of outliers. The sample is small but the stemplot is not skewed, so the outliers. The sample is small but the stemplot is not skewed, so the use of t use of t procedures is appropriate. O The stemplot does not indicate the presence of outliers. The sample is small and the stemplot of t procedures is not appropriate. skewed, so the use (b) 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 two 90% confidence intervals, one with all the data and one 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. Use Table Cor the software of your choice for these calculations. (Enter your answers rounded to three decimal places.) lower bound an data = (c) Compare the two intervals in part (b). What is the most important effect of removing the outliers? upper bound ta = O increasing of confidence interval O reducing margins of error lower bound outlien remned= O reducing of confidence interval O simplification of calculations upper boundutliers remened =