(A-Grade) The operations manager of a large production plantwould like to estimate the mean amount of time a worker takes toassemble a new electronic component. Assume that the populationstandard deviation of time for this assembly is 3.6 minutes.
1. After observing 120 workers assembling similar devices, themanager noticed that their average time was 16.2 minutes. Constructa 92% confidence interval for the mean assembly time.
2. How many workers should be involved in this study in order tohave the mean assembly time estimated up to 15 seconds with 92%confidence?
3. In a second study a sample 102 workers had standard deviationof 2.78 minutes, with 95% confidence level, construct a confidenceinterval for the population standard deviation.
