Exam 11: Analyzing Experimental Data: Basic Concepts

Which of the following 95% confidence intervals for the difference between two means most likely indicates that the two means are truly different from one another in the population?

What is a null hypothesis?

The alpha-level that researchers generally use is designed to ensure Type I errors occur on less than _____ of statistical decisions.

Failing to reject the null hypothesis when it is false is

A power analysis is often used to determine

A 95% confidence interval (CI)

Distinguish among the three kinds of effect size indicators.

A Type I error occurs when a researcher

The null hypothesis states that

Discuss three problems that are associated with null hypothesis significance testing.

From looking at a 95% confidence interval for the difference between two means, how can we tell whether the two means are significantly different?

A difference between means that is statistically significant is

Null hypothesis significance testing has been criticized because

What information does a 95% confidence interval provide?

A Type I error can occur only when a researcher

Why is it insufficient for a researcher to simply inspect the condition means to determine whether the independent variable affected scores on the dependent variable?

In deciding whether to reject the null hypothesis, researchers may make one of two errors. Explain.

Type II errors are more likely when

Based on statistical analyses, a researcher will make one of two decisions regarding the null hypothesis. What are they?

Cohen's d expresses the size of an effect in terms of