Question

For problems 7 and 8, an auto manufacturer claims that the average length of time that one of its cars is owned before it requires a major repair is at least seven years. Assume that a survey of ten owners of the manufacture's ears finds that they went an average of 6 years before a major repair and the sample standard deviation for such time lengths was 18 years. Use the data to test the manufacture's claim at a 5% significance level 7. Give the null hypothesis and alternative hypothesis and critical value(s) used to test this claim. 8. Give the test statistic and use this to test the manufacturer's claim at a 5% significance level and draw a conclusion based on this. For problems 9 and 10, a machine shop claims that the measurements of the parts it produces are uniform with a standard deviation of 1.3 millimeters. A test sample of 31 parts from the shop has a standard deviation of 1.8 millimeters. 9. Give the null and alternative hypothesis and critical value(s). 10. Give the test statistic and use this to find if this result contradicts the shop's claim at a 10% level of significance

there are 4 questions collectively. thanks!

Answer 1

According to the rules only first question will be answered. If you are not getting then please send comment.

7) Nal Hypothesis Ho: u>7 Alternative Hypothesis: Ha! u<1 (left-tailed test). level of significance & =0.05 2x/2 = 7.6us Test - Statistic: Z=x-u olun 6-7 1.8lun =-in (need Sample size ). n=10 is given. 1.8 =- Vio 18 =-1-7568 Izlcal > Izleab. Conclusion : Hence, we reject to at 5%. LO.S.