5. Machine accuracy. A machine in a plant manufactures a car part and is set to make the part 6.70 in. long. The shift supervisor is responsible for making sure the setting on the machine has not shifted and altered the length of the part in either direction. One day a sample of n = 36 of these parts was randomly taken from the assembly line and measured for length. The supervisor found that the mean length was 6.83 in. and 52 = 0.1024. (16 marks total) a. Construct a 95% confidence interval estimate of the mean number of chocolate chips in all such cookies. Hint: Use the closest degree of freedom or extrapolate if in the middle between two degrees of freedom. (12 marks) b. Should the supervisor change the settings on the machine? Explain why. (4 marks)