# Question

While waiting in a long line for service (e.g., to use an ATM or at the post office), at some point you may decide to leave the line. The Journal of Consumer Research (Nov. 2003) published a study of consumer behavior while waiting in a line. College students (sample size n = 148) were asked to imagine that they were waiting in line at a post office to mail a package and that the estimated waiting time was 10 minutes or less. After a 10-minute wait, students were asked about their level of negative feelings (annoyed, anxious) on a scale of 1 (strongly disagree) to 9 (strongly agree). Before answering, however, the students were informed about how many people were ahead of them and behind them in the line. The researchers used regression to relate negative feelings score (y) to number ahead in line (x1) and number behind in line (x2).

a. The researchers fit an interaction model to the data. Write the hypothesized equation of this model.

b. In the words of the problem, explain what it means to say that “x1 and x2 interact to affect y.”

c. A t-test for the interaction b resulted in a p-value greater than .25. Interpret this result.

d. From their analysis, the researchers concluded that “the greater the number of people ahead, the higher [is] the negative feeling score” and “the greater the number of people behind, the lower [is] the negative feeling score.” Use this information to determine the signs of β1 and β2 in the model.

a. The researchers fit an interaction model to the data. Write the hypothesized equation of this model.

b. In the words of the problem, explain what it means to say that “x1 and x2 interact to affect y.”

c. A t-test for the interaction b resulted in a p-value greater than .25. Interpret this result.

d. From their analysis, the researchers concluded that “the greater the number of people ahead, the higher [is] the negative feeling score” and “the greater the number of people behind, the lower [is] the negative feeling score.” Use this information to determine the signs of β1 and β2 in the model.

## Answer to relevant Questions

An International Journal of Research (March 2010) study of the influence of reality TV shows on one’s desire to undergo cosmetic surgery, Exercise 12.23 (p. 631). Recall that psychologists modeled desire to have cosmetic ...MINITAB was used to fit the complete second-order model E(y) = β0 + β1x1 + β2x2 + β3x1x2 + β4x12 + β5x22 To n = 39 data points. (See the MINITAB printout on page 652.) a. Is there sufficient evidence to indicate that ...The optomotor responses of tree frogs were studied in the Journal of Experimental Zoology (Sept. 1993). Microspectrophotometry was used to measure the threshold quantal flux (the light intensity at which the optomotor ...Consider a multiple-regression model for a response y with one quantitative independent variable x1 and one qualitative variable at three levels. a. Write a first-order model that relates the mean response E(y) to the ...Suppose you fit the regression model y = β0 + β1x1 + β2x2 + β3x1x2 + β4x21 + β5 x22 + ε to n = 30 data points and you wish to test H0: β3 = β4 = β5 = 0 a. State the alternative hypothesis Ha. b. Give the reduced ...Post your question

0