Exam 13: Why We Need Statistics

Applying Statistical Inference: An Example If you reject the null hypothesis when it is actually true,

Applying Statistical Inference: An Example Many statistical tests assume that the population you have sampled is normally distributed.This means that if you could measure everyone in the population on the dependent variable,

Applying Statistical Inference: An Example If an experimenter finds that the difference between two treatment groups is significant at the .05 level, then

Applying Statistical Inference: An Example All of these statements about experimental error are correct except:

Test Statistics All of these terms belong together except

Weighing the Evidence Dr.M.predicted that heart rate variability biofeedback would reduce depressive symptoms.She randomly assigned depressed patients to either receive 2 hours of heart rate variability training or 2 hours of yoga instruction and measured changes in Beck Depression Inventory scores.Since the heart rate variability group improved more than the yoga group, she

Weighing the Evidence We are more likely to reject the null hypothesis when

Weighing the Evidence The ____ hypothesis states that the performance of the treatment groups is so similar that the scores must have been sampled from the same population.

Applying Statistical Inference: An Example Typically, researchers

Organizing and Summarizing Data The ____ tells us whether scores are spread out a great deal or tightly clustered around the mean.

Weighing the Evidence Statistical significance means that

Organizing and Summarizing Data To find the range of a set of scores, we calculate the

The Argument for Using Statistics Statistics are

Applying Statistical Inference: An Example Marty studied whether tattoos affect employer perception of job applicant responsibility.Although the independent variable (tattoo) did not really affect employer perceptions, differences in how he treated each treatment group caused him to mistakenly reject the null hypothesis.Marty's decision illustrates

Weighing the Evidence A ____ consists of all people, animals, or objects that share at least one characteristic in common.

Weighing the Evidence H₀ represents the

Weighing the Evidence Students surveyed about the number of MP3s they download each week report widely diverse numbers.This pattern of results illustrates what we mean by

Organizing and Summarizing Data Two distributions that have the same variance must also have the same

Organizing and Summarizing Data Based on the range, which of the following sets of scores has the greatest variability?

Applying Statistical Inference: An Example Calvin has set his alpha level at .05.He will reject the null hypothesis if he observes a difference between treatment conditions that is so large that it could have occurred by chance