A random sample of 10 shipments of stick-on labels showed the following order sizes. 12,000 18,000 30,000 60,000 14,000 10,500 52,000 14,000 15,700 19,000 Click here for the Excel Data File (a) Construct a 95% confidence interval for the true mean order size. (Round your standard deviation answer to 1 decimal place and t-value to 3 decimal places. Round your answers to the nearest whole number.) The 95% confidence interval to (b) The confidence interval could be made narrower by: decreasing the sample size or decreasing the confidence level. increasing the sample size or decreasing the confidence level. decreasing the sample size or increasing the confidence level. increasing the sample size or increasing the confidence level.