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Many cardiac patients wear an implanted pacemaker to control their heartbeat. A plastic connector module mounts on the top of the pacemaker. A random sample of 85 modules has an average depth of 0.310 inch. Assuming a standard deviation of 0.0019 inch and an approximately normal distribution, a 90% confidence interval for the mean of the depths of all connector modules made by a certain manufacturing company was found to be 0.3097 <<0.3103. How large a sample is needed if we wish to be 90% confident that our sample mean will be within 0.0008 inch of the true mean? Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. The required sample size is at least (Round up to the nearest whole number as needed.) ←
A machine produces metal pieces that are cylindrical in shape. A sample of pieces is taken, and the diameters are found to be 0.94, 0.96, 0.97, 1.05, 0.99, 0.98, 1.02, 0.94, and 0.94 centimeters. Find a 90% confidence interval for the mean diameter of pieces from this machine, assuming an approximately normal distribution. Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. The confidence interval is<μ<. (Round to three decimal places as needed.) ←
The measurements given below were recorded for the drying time, in hours, of a certain brand of latex paint. Assuming that the measurements represent a random sample from a normal population, find a 90% prediction interval for the drying time for the next trial of the paint. 3.5 5.2 5.7 4.3 3.7 2.6 2.9 4.9 3.4 3.8 3.5 The prediction interval is<x0 <- (Round to two decimal places as needed.) 4.6 2.7 4.3 4.3 Click here to view page 1 of the standard normal distribution table. Click here to view page 2 of the standard normal distribution table. Click here to view page 1 of the table of critical values of the t-distribution. Click here to view page 2 of the table of critical values of the t-distribution. C