Exam 10: Comparing More Than Two Means

As the Mean Group Diff statistic increases, the p-value also increases.

When performing an ANOVA F-test, which definition of a p-value is the most accurate?

A simulated null distribution of the Mean Group Diff statistic will always be symmetric.

College students tested to see if how well you know a person affects your ability to detect a lie from that person. To do this, they came up with 10 statements about a person in their group. Five of these statements were true and five were False. The group tried to make up statements that no-body (not even close friends) would know if they were true or False. The students then presented these statements to people that fit in three groups: close friends, acquaintances, and complete strangers and counted how many statements each person correctly identified as true or False. A summary of the results are as follows. -Compute the Mean Group Diff statistic for this data set.

In a neurological study of the effect of environment on mental development, rats were randomly assigned to be raised in one of the four following test conditions: Impoverished (wire mesh cage - housed alone), Standard (cage with other rats), Enriched (cage with other rats and toys), and Super Enriched (cage with other rats and toys changed on a periodic basis). After two months, the rats were tested on a variety of learning measures, one of them being the number of attempts needed to learn to navigate a maze. The data for the maze task are below, along with means and standard deviation for each group. -Suppose that, in reality, there is no association between test condition and number of attempts needed to learn to navigate a maze. Which of the following sets of tests would have the largest probability of at least one Type I error?

A British study examined whether the type of background music playing in a restaurant affected the amount of money that diners spent on their meals. The researchers asked a restaurant to alternate silence, popular music, and classical music on successive nights over eighteen days. Each type of music was played for 6 nights (the order was randomly determined to guard against confounding). The type of music played and the amount spent on food and drinks (in British pounds) for each of 393 customers was recorded. The data are summarized below. -Follow-up 95% confidence intervals are presented below. • • • The mean amount spent when pop music is playing is significantly lower than the mean amount spent when classical music is playing.

A British study examined whether the type of background music playing in a restaurant affected the amount of money that diners spent on their meals. The researchers asked a restaurant to alternate silence, popular music, and classical music on successive nights over eighteen days. Each type of music was played for 6 nights (the order was randomly determined to guard against confounding). The type of music played and the amount spent on food and drinks (in British pounds) for each of 393 customers was recorded. The data are summarized below. -Which of the following validity conditions are met to conduct an ANOVA F-test on these data? Select all that apply.

In a neurological study of the effect of environment on mental development, rats were randomly assigned to be raised in one of the four following test conditions: Impoverished (wire mesh cage - housed alone), Standard (cage with other rats), Enriched (cage with other rats and toys), and Super Enriched (cage with other rats and toys changed on a periodic basis). After two months, the rats were tested on a variety of learning measures, one of them being the number of attempts needed to learn to navigate a maze. The data for the maze task are below, along with means and standard deviation for each group. -What are the observational units?