1. A survey carried out by the professional engineers describes several characteristics of fuel rods used in a reactor owned by an electric utility in Damansara. From the record, the true standard deviation is 3 and the measurements on the percentage of enrichment of 12 rods were reported as follows: 2.94 3.00 2.90 2.75 3.00 2.95 2.90 2.75 2.95 2.82 2.81 3.05 Assume that the percentage of enrichment follows normal distribution. i. Construct a 99% confidence interval on the mean of enrichment of fuel rods. ii. An officer claimed that the overall variance of the of enrichment of fuel rods is similar to the recorded value. Test whether the officer's claim is true at significance level a = 0.025. iii. If level of significance is reduced to 0.02, will you change the conclusions you have made in (ii)? Justified your answer.