Draw the graph of a two-tailed test.

Short Answer

Expert verified

A two-tailed test results from an alternative hypothesis that does not specify a direction. A two-tailed test has two critical regions.

Step by step solution

01

Diagram

A Diagram showing a two-tailed test.

02

Explanation

A two-tailed test signifies that we're looking for an area in the middle of the distribution. Alternatively, your rejection region ( where one rejects the null hypothesis) is on both ends of the tails.

A two-tailed test is required when the degree of uncertainty cannot be known on the higher or lower side.

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Most popular questions from this chapter

"Untitled," by Stephen Chen

I've often wondered how software is released and sold to the public. Ironically, I work for a company that sells products with known problems. Unfortunately, most of the problems are difficult to create, which makes them difficult to fix. I usually use the test program X, which tests the product, to try to create a specific problem. When the test program is run to make an error occur, the likelihood of generating an error is1%.

So, armed with this knowledge, I wrote a new test program Y that will generate the same error that test programX creates, but more often. To find out if my test program is better than the original, so that I can convince the management that I'm right, I ran my test program to find out how often I can generate the same error. When I ran my test program50 times, I generated the error twice. While this may not seem much better, I think that I can convince the management to use my test program instead of the original test program. Am I right?

Previously, an organization reported that teenagers spent 4.5hours per week, on average, on the phone. The organization thinks that, currently, the mean is higher. Fifteen randomly chosen teenagers were asked how many hours per week they spend on the phone. The sample mean was 4.75hours with a sample standard deviation of 2.0. Conduct a hypothesis test, the Type I error is:

a. to conclude that the current mean hours per week is higher than 4.5, when in fact, it is higher

b. to conclude that the current mean hours per week is higher than 4.5, when in fact, it is the same

c. to conclude that the mean hours per week currently is 4.5, when in fact, it is higher

d. to conclude that the mean hours per week currently is no higher than 4.5, when in fact, it is not higher

When a new drug is created, the pharmaceutical company must subject it to testing before receiving the necessary permission from the Food and Drug Administration (FDA) to market the drug. Suppose the null hypothesis is “the drug is unsafe.” What is the Type II Error?

a. To conclude the drug is safe when in, fact, it is unsafe.

b. Not to conclude the drug is safe when, in fact, it is safe.

c. To conclude the drug is safe when, in fact, it is safe.

d. Not to conclude the drug is unsafe when, in fact, it is unsafe.

Determine both TypeIand TypeIIerrors for the following scenario:

Assume a null hypothesis,H0, that states the percentage of adults with jobs is at least 88%.

Identify the TypeIand Type IIerrors from these four statements.

a. Not to reject the null hypothesis that the percentage of adults who have jobs is at least 88%when that percentage is actually less than 88%

b. Not to reject the null hypothesis that the percentage of adults who have jobs is at least 88%when the percentage is actually at least 88%.

c. Reject the null hypothesis that the percentage of adults who have jobs is at least 88%when the percentage is actually at least 88%.

d. Reject the null hypothesis that the percentage of adults who have jobs is at least 88%when that percentage is actually less than 88%.

For statements a-j ( Section: 9.109 ), answer the following in complete sentences.

a. State a consequence of committing a Type I error.

b. State a consequence of committing a Type II error.

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