Solve the following problems. Show all solutions.
1. A manufacturer of bicycle tires has developed a new design which he claims has an average lifespan of 5 years. A random sample of 150 tires showed a mean of 3.5 years with a standard deviation of 1.2 years. Test the claim at 5% level of significance.
2. A company which makes toy cars claims that its products have a mean life span of more than 5 years. Test the claim at 5% level of significance if a random sample of 28 toy cars was found to have a mean life span of 5.2 years with a standard deviation of 1.5 years.
Answers
Answer:
1. A manufacturer of bicycle tires has developed a new design which he claims has an average lifespan of 5 years. A random sample of 150 tires showed a mean of 3.5 years with a standard deviation of 1.2 years. Test the claim at 5% level of significance.
2. A company which makes toy cars claims that its products have a mean life span of more than 5 years. Test the claim at 5% level of significance if a random sample of 28 toy cars was found to have a mean life span of 5.2 years with a standard deviation of 1.5 years.
Answer:
Some of the following statements refer to the null hypothesis, some to the alternate hypothesis.
State the null hypothesis, H0 , and the alternative hypothesis. Ha , in terms of the appropriate parameter (μorp) .
The mean number of years Americans work before retiring is 34.
At most 60% of Americans vote in presidential elections.
The mean starting salary for San Jose State University graduates is at least $100,000 per year.
Twenty-nine percent of high school seniors get drunk each month.
Fewer than 5% of adults ride the bus to work in Los Angeles.
The mean number of cars a person owns in her lifetime is not more than ten.
About half of Americans prefer to live away from cities, given the choice.
Europeans have a mean paid vacation each year of six weeks.
The chance of developing breast cancer is under 11% for women.
Private universities' mean tuition cost is more than $20,000 per year.