Question

A shipping firm suspects that the mean life of a certain brand of tire used by...

A shipping firm suspects that the mean life of a certain brand of tire used by its trucks is less than 39,000 miles. To check the claim, the firm randomly selects and tests 18 of these tires and gets a mean lifetime of 38,350 miles with a standard deviation of 1200 miles. At α = 0.05, test the shipping firm's claim.

Find the test statistic, t. p value and null hypothesis Round to four decimal places.

Math   Statistics-And-Probability   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

Given:

Population mean, = 39000

Sample mean, = 38350

Standard Deviation, = 1200

Sample size, n = 18

Significance level, = 0.05

Hypothesis test:

Null Hypothesis H0 : = 39000
Alternate Hypothesis Ha : < 39000 (This a left tailed test)

Since p-value is less than the significance level of α = 0.05, so we reject the null hypothesis, H0 and conclude that the mean life of the tires used by the firm is less than 39,000 miles.

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
A trucking firm suspects that the mean life of a certain tire it uses is less...
A trucking firm suspects that the mean life of a certain tire it uses is less than the advertised 45,000 miles. To check the claim, the firm randomly selects and tests 22 of these tires and gets a mean lifetime of 44,350 miles with standard deviation of 1200 miles. a) The sample mean is 44,350. Before doing any work, what is gut feeling about the chances of the population mean being less than or equal to 45,000? Do you think...
Make sure to show all steps to receive full credit, that is: a) Identify the claim:...
Make sure to show all steps to receive full credit, that is: a) Identify the claim: state the null and alternative hypotheses. b) Determine the test: left-tailed, right-tailed, or two-tailed. c) Graph your bell-shaped curve and label your levels of significance or critical value. d) Find your standardized test statistic ? and label it on your graph. e) Decide whether to reject or fail to reject the null hypothesis. f) Interpret your result. 1) A dealership projected that the mean...
A particular brand of tires claims that its snow tire averages less than 50,000 miles before...
A particular brand of tires claims that its snow tire averages less than 50,000 miles before it needs to be replaced. From past studies of this tire, the standard deviation is known to be 8,000. A survey of owners of that tire design is conducted. From the 28 tires surveyed, the mean lifespan was 46,500 miles with a standard deviation of 9,800 miles. Using α = 0.05 to test the claim.
The lifetime of a certain automobile tire is normally distributed with mean 40 (thousand miles) and...
The lifetime of a certain automobile tire is normally distributed with mean 40 (thousand miles) and standard deviation 5 ( thousand miles). if 8 tires are randomly selected, there would be an 83% probability that the mean tire lifetime would fall between what two values.
1. A company claims that the average lifespan of a bicycle tire that they manufacture is...
1. A company claims that the average lifespan of a bicycle tire that they manufacture is 1200 miles. You randomly and independently collect a sample of 31 of these tires and find that the average distance these tires lasted was 1125.7 miles, with a standard deviation of 275 miles. A 90% confidence interval for the population mean lifetime of these tires is (1041.9, 1209.5). Select all true statements. a. The confidence interval indicates that the company's claim that their tires...
A particular brand of tires claims that its deluxe tire averages at least 50,000 miles before...
A particular brand of tires claims that its deluxe tire averages at least 50,000 miles before it needs to be replaced. From past studies of this tire, the standard deviation is known to be 8,000. A survey of owners of that tire design is conducted. Of the 29 tires surveyed, the mean lifespan was 46,600 miles with a standard deviation of 9,800 miles. Using alpha = 0.05, is the data highly consistent with the claim? Note: If you are using...
A lifetime of certain brand of tires is normally distributed with the mean of 80, 000...
A lifetime of certain brand of tires is normally distributed with the mean of 80, 000 kilometers and a standard deviation of 6000 kilometers. a. Probability that a randomly selected tire will have lifetime 70,000 kilometers or more is __________ b. The percent of tires with lifetimes between 65, 000 kilometers and 85, 000 kilometers is ______________ c. The manufacturer of tires wants to establish the warranty on the tires. He wants to replace for free only 4% of the...
A tire manufacturer claims that his tires have a mean life of 60,000 miles when used...
A tire manufacturer claims that his tires have a mean life of 60,000 miles when used under normal driving conditions. A firm that requires a larger number of these tires wants to test the claim. If the claim is correct, the firm will purchase the manufacturer’s tires; otherwise, the firm will seek another supplier. Now a random sample of 100 tires is taken and the mean and standard deviation of the 100 tires are found. Using these sample results, a...
A tire manufacturer claims that his tires have a mean life of 60,000 miles when used...
A tire manufacturer claims that his tires have a mean life of 60,000 miles when used under normal driving conditions. A firm that requires a larger number of these tires wants to test the claim. If the claim is correct, the firm will purchase the manufacturer’s tires; otherwise, the firm will seek another supplier. Now a random sample of 100 tires is taken and the mean and standard deviation of the 100 tires are found. Using these sample results, a...
A tire manufacturer claims that his tires have a mean life of 60,000 miles when used...
A tire manufacturer claims that his tires have a mean life of 60,000 miles when used under normal driving conditions. A firm that requires a larger number of these tires wants to test the claim. If the claim is correct, the firm will purchase the manufacturer’s tires; otherwise, the firm will seek another supplier. Now a random sample of 100 tires is taken and the mean and standard deviation of the 100 tires are found. Using these sample results, a...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT