- A Random Sample Of 17 Shearing Pins Is Taken In A Study Of The Rockwell Hardness Of The Pin Head Measurements On The Ro 1 (19.55 KiB) Viewed 42 times
A random sample of 20 chocolate energy bars of a certain brand has, on average, 230 calories per bar, with a standard deviation of 35 calories. Construct a 99% confidence interval for the true mean calorie content of this brand of energy bar. Assume that the distribution of the calorie content is approximately normal. 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 << (Round to one decimal place as needed.) (...)
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<μ<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.) C