(a) A growing sector of the plastics industry, plastic injection moulding is the most common process used to produce plastic parts. The process of plastic injection moulding is fast, meant to produce large quantities of the same plastic product in a short time span. To control the quality of the process, the mean weight of plastic parts was kept at the accuracy of 0.8 grams with a confidence level of 90%. Given that the population standard deviation of the plastic parts is 5 grams. (i) Estimate the appropriate number of sample size required so it is within the accuracy limit. (ii) Suppose the accuracy has decreased to 0.5 with the confident level of 99%, estimate the appropriate sample size. (iii) Discuss the effect of changing the accuracy limit and the confident level in terms of sample size