Job satisfaction scores reported by teachers from a certain…

Job satisfaction scores reported by teachers from a certain school district are known to be normally distributed with a population standard deviation of 14.5 points. In a random sample of 21 teachers from this school district, the mean job satisfaction score was 62.91. A 95% confidence interval estimate for the mean job satisfaction score of this population is to be constructed using this sample data. What z-score should be used to construct a 95% confidence interval estimate for the mean? [z] What is the lower limit for this confidence interval estimate of the mean? [lower] What is the upper limit for this confidence interval estimate of the mean? [upper]