Statistics Alpha Beta Power

Tammy wants to see who will vote for candidate A for the next Maryland governor. She believes just 40% of the population in MD will vote for A. However based on a sample she obtained this result might be too low. Here are her hypotheses: H0: p = .4 vs Ha: p > .4. She checked her conditions and performed a test and got a p-value of 0.01. Her power was 0.45. Which of the following is the correct interpretation of power?

• There is a 1% chance that she has convincing evidence that more than 40% voted for A.

• There is a 45% chance that she has convincing evidence that more than 40% voted for A.

• There is a 45% chance that she does not have convincing evidence that more than 40% voted for A.

• There is a 45% chance that she has convincing evidence that 40% voted for A.

• There is a 1% chance that she has convincing evidence that 40% voted for A.

Tammy wants to see who will vote for candidate A for the next Maryland governor. She believes just 40% of the population in MD will vote for A. However based on a sample she obtained this result might be too low. Here are her hypotheses: H0: p = .4 vs Ha: p > .4. She uses a 0.05 significance level. She checked her conditions and performed a test and got a p-value of 0.01. Her power was 0.45. What is beta?

• 0.6

• 0.99

• 0.95

• 0.55

Which of the following is the best definition of standard deviation?

• • The average of the sum of squared deviations from the mean.

• • The typical amount by which scores differ from the mean of a set of scores.

• • The average of a set of scores.

• The mean squared deviation from the average.

A rejection of the null hypothesis when in reality it should have been accepted is described as a ...

• • safety probability.

• • statistical power.

• • Type I error.

• Type II error.

Which of the following is correct?

• • The smaller the p-value the bigger the effect size.

• • The p-value measures the probability that the Null hypothesis is true.

• • The power of a test depends upon the sample size, two- or one-sided test, and the distance between the expected values of the sampling distribution under the null and alternative hypothesis.

• • The rejection region is controlled by the alpha level.

Which statements are true? The bigger the standard deviation the …

• bigger the mean.

• • more people differ in their answers.

• • bigger the variance.

• • closer to the mean are most values.

Which of the following is a correct interpretation of a significant t-test result when comparing two mean scores using an alpha level of .05?

• There is a less than 5% chance the observed difference is a result of the treatment.

• • There are no differences between the means.

• • The probability of obtaining a result equal to or "more extreme" than what was actually observed, given the null hypothesis is true is less than 5%.

• • There are differences between the sample means but they are caused by sampling errors.

The probability of rejecting the null hypothesis when it is true is called as

• Level of confidence

• Level of significance

• Power of a test

• None of these