Q 86

________ variables may be used as predictors or independent variables by coding them as dummy variables.
A)Interval
B)Categorical
C)Ratio
D)All of the above

Q 87

The regression equation for a categorical variable with four categories would be modeled as ________.
A)Ŷ_{ }_{i }= a + b_{1} D_{1 + }b_{2} D_{2 + }b_{3}D_{3 }
B)Ŷ_{ }_{i }= a + b_{1} D_{1 + }b_{2} D_{2 + }b_{3}D_{3 +} b_{4}D_{4 }
C)Ŷ = b_{1} D_{1 + }b_{2} D_{2 + }b_{3}D_{3 }
D)Ŷ = b_{1} D_{1 + }b_{2} D_{2 + }b_{3}D_{3 +} b_{4}D_{4 }

Q 88

Suppose a researcher wants to explain attitudes towards a respondent's city of residence in terms of duration of residence in the city. The attitude is measured on an 11-point scale and the duration of residence is measured in terms of the number of years the respondent has lived in the city. In a pretest of 12 respondents, the calculated t value for the correlation coefficient based on the data given is 8.414. The critical value of t for a two-tailed test and α = 0.05 is 2.228. r = .9361. What is the null hypothesis for this scenario? What do the results mean in terms of the null hypothesis and the correlation coefficient, r?