Exam 10: Introduction to Hypothesis Testing: Using the Sign Test

As the probability of making a Type I error goes down by making a more stringent, the probability of making a Type II error goes up.

A psychologist is interested in whether hypnosis affects brain dominance. Twelve college students from the freshmen class are randomly sampled for an experiment. The experiment has two conditions which are given on different days. In condition 1, the students are hypnotized and then given a test which measures the relative dominance of the right and left hemispheres. The higher the score, the more dominant is the right hemisphere. In condition 2, the same students are given the test again, only this time they are not hypnotized but are in their normal state of consciousness. The following scores are obtained. The null hypothesis appropriate for a nondirectional alternative hypothesis is _________.

Using the sign test, is the probability of making a Type I error equal to alpha? Why or why not? Illustrate, using an example and appropriate calculations.

If you reject H₀ when H₀ is false, you have made a _________.

The statement "Drug X has no effect on Y and any observed effect is due to chance alone" is an example of a nondirectional alternative hypothesis.

It is always appropriate to use a directional H 1 .

A social scientist wants to determine if showing a film will affect religious tolerance. A sample of freshman males was drawn from a university. Pre and post film ratings of religious tolerance were obtained. A higher number represents higher tolerance. The following data were obtained:

The null hypothesis which is appropriate for a directional alternative hypothesis asserts that _________.

The nondirectional alternative hypothesis asserts that _________.

The critical probability for rejecting H₀ is the alpha level.

If the result turns out to be in the direction opposite to a directional H 1 , we must conclude by retaining H 0 .

Type I errors are always worse to make than Type II errors.

An alpha level of 0.05 indicates that _________.

The alternative hypothesis must be nondirectional.

The value used for alpha depends on the consequences of making a Type I and Type II error.

The more stringent the alpha level is, the easier it is to detect an effect of the independent variable on the dependent variable.

H₀ and H₁ must be mutually exclusive and exhaustive.

An after-shave company recently advertised that if you use their product you will have more sex appeal. To test this claim you enlist the assistance of 12 men from a local social club. The men are either given the new after-shave or colored water. After one month the type of liquid each man had been using was changed to the other type; i.e., water changed for after-shave or after-shave for water. The experiment continued for another month. The dependent variable was the number of dates each man had for each month. The results are shown in the following table .

In the sign test, if the null hypothesis is true, then P _________.

The following probabilities are the results of several different experiments.