METAL INGOT CASTING OPERATIONS.xISX QUESTION 1(a): SAMPLING DISTRIBUTION (3 POINTS) In the Excel file, you are provided data on the typical percentage of all ingots manufactured at your assigned operation which are cracked. During the first month of your assignment, you randomly select a batch of ingots. What is the probability that this batch will have less than the indicated percentage (in Excel) which are cracked? QUESTION 1(b): CONFIDENCE INTERVAL (5 POINTS) At the beginning of the second month, you randomly select another batch of ingots, and count how many of them are cracked. You want to find a confidence interval for the percentage of all ingots manufactured that month which will be cracked. QUESTION 1(c): HYPOTHESIS TEST (5 POINTS) In an attempt to reduce the number of cracked ingots, the engineers and chemists at your location made changes to the casting process. During the third month, you randomly select another batch of ingots, and count how many of them are cracked. Based on the results on this third batch, compared to the typical level of cracked ingots indicated in part 1(a), would you conclude that the changes were successful or not? QUESTION 2: CONFIDENCE INTERVAL (5 POINTS) In your fourth month, you are asked to also take a look at impurity levels in ingots. You randomly select a fourth batch of ingots, and work with the chemists to determine impurity levels measured in ppm (parts per million). Based on these results, you want to estimate, to a certain degree of confidence, what the mean level of impurities will be for all ingots manufactured that month. Click Save and Submit to save and submit. Click Save All Answers to save all answers