3. The errors in a chemistry experiment are normally distributed with mean 1.2 errors and variance 4.5 BI'I'OI'S2 . A. What is the probability that an experiment will have more than 2 errors? B. If 10 such experiments are randomly selected, what is the probability that their average number of errors is more than 2? 4. Universities are becoming more concerned about the proportion of students who use portable audio (earbuds, headphones. . .etc.) While attending classes. A random sample of 500 university students was selected and 80 students conrmed that they use portable audio while attending classes. A. Find the 95% condence interval for the students who use their portable audio while attending classes. B. Does the study provide enough evidence to conclude that the proportion of students who use portable audio while attending class is less than 15%? Use a : 0.10