A machine produces metal rods used in an automobile suspension system. A random sample of 15 rods and the diameter is measured. The resulting data (in millimeters) are as follows:8.24 | 8.25 | 8.20 | 8.23 | 8.24 |8.21 | 8.26 | 8.26 | 8.20 | 8.25 |8.23 | 8.23 | 8.19 | 8.28 | 8.24 |-) Calculate a 95% two - sided confidence interval on mean rod diameter-) Calculate a 95% upper confidence bound on the mean. Compare this bound withe the upper bound of the two - sided confidence interval ad discuss why they are diffrence
I've had dextero tires on my jeep Cherokee for about 7-8 months now. No problems and they are a smooth ride. Went in and they were on sale for $60/each. Never heard of Dextero so I got the warranty and a pro rated so when ever they wear out.I get a good deal on new tires :)
ANSWER: 95% Resulting Confidence Interval for 'true mean': [8.22, 8.248] Why?? SMALL SAMPLE, CONFIDENCE INTERVAL, NORMAL POPULATION DISTRIBUTION x-bar Sample mean 8.234 s Sample standard deviation0.025 n Number of samples 15 df degrees of freedom 14 significant digits3 Confidence Level95 Look-up Table 't-critical value'2.145 from Excel function: TINV(probability,degrees_freedom) Returns the inverse of the Student's t-distribution 95% Resulting Confidence Interval for 'true mean': x-bar +/- ('t critical value') * s/SQRT(n) 8.234 +/- 2.145 * 0.025/SQRT(15) [8.22, 8.248] ANSWER: 95% Upper Confidence Bound on the Error of Estimation (mean) 8.247 compared to 8.248 Computation: 1.96*0.025/SQRT(15), The point estimate x-bar is not farther than this from the population mean.
