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Do blondes raise more funds? During fundraising, does the physical appearance of the solicitor impact the level of capital raised? An economist at the University of Nevada- Reno designed an experiment to answer this question and published the results in Economic Letters (Vol. 100, 2008). Each in a sample of 955 households was contacted by a female solicitor and asked to contribute to the Center for Natural Hazards Mitigation Research. The level of contribution (in dollars) was recorded as well as the hair color of the solicitor (blond Caucasian, brunette Caucasian, or minority female).

a) Consider a model for the mean level of contribution, E(y), that allows for different means depending on the hair color of the solicitor. Create the appropriate number of dummy variables for hair color. (Use minority female as the base level.)

b) Write the equation of the model, part a, incorporating the dummy variables.

c) In terms of the b鈥檚 in the model, what is the mean level of contribution for households contacted by a blond Caucasian solicitor?

d) In terms of the b鈥檚 in the model, what is the difference between the mean level of contribution for households contacted by a blond solicitor and those contacted by a minority female?

e) One theory posits that blond solicitors will achieve the highest mean contribution level, but that there will be no difference between the mean contribution levels attained by brunette Caucasian and minority females. If this theory is true, give the expected signs of the鈥檚 in the model.

f) The researcher found the b estimate for the dummy variable for blond Caucasian to be positive and significantly different from 0 (p-value < 0.01). Theestimate for the dummy variable for brunette Caucasian was also positive, but not significantly different from 0 (p-value < 0.10). Do these results support the theory, part e?

Short Answer

Expert verified

a) For k no of level, the dummy variable created in the model is (k-1). Since here, there are 3 levels, 2 dummy variable x1 and x2 will be created where x1 represents a female with blond Caucasian hair color and x2 represents a female with brunette Caucasian hair color.

b) A model with 2 dummy variables can be written as y=0+1x1+2x2where x1represents female with blond Caucasian hair color and x2represents female with brunette Caucasian hair color.

c) The mean contribution level for households contacted by a blond Caucasian solicitor is represented when thus the value of contribution can be summarized.

d) The mean level of difference in contribution for households contacted by a blond solicitor and those contacted by a minority female is represented by1.

e) 0will be positive since it represents the level of contribution of a household at the base level (which here is when the solicitor is minority female). 1will also be positive since the theory posits that the blond solicitors will collect the highest mean contribution level.2 will not be recorded in the model since the mean contribution levels of brunette Caucasian and minority female is the same.

f) To check whether1 is different from 0, theH0:1 while H0:10. Since the value of the p-value is given to be less than 0.01 which indicates that the value of 1is not zero. However, for2 the value is coming to be positive but not significantly different from 0 since the p-value is greater than 0.10 thus the value of 2will be 0.

Step by step solution

01

Creating dummy variables

For k no of level, the dummy variable created in the model is (k-1). Since here, there are 3 levels, 2 dummy variable x1 and x2 will be created where x1 represents female with blond Caucasian hair color and x2 represents female with brunette Caucasian hair color.

02

Dummy variable model

A model with 2 dummy variables can be written as representing a female with blond Caucasian hair color and a female with brunette Caucasian hair color.

03

Interpretation of β

The mean contribution level for households contacted by a blond Caucasian solicitor is represented when thus the value of contribution can be summarized.

04

Analysis of β

The mean level of difference in contribution for households contacted by a blond solicitor and those contacted by a minority female is represented by.1

05

Signs of β’s

0will be positive since it represents the level of contribution of a household at the base level (which here is when the solicitor is a minority female)

1will also be positive since the theory posits that the blond solicitors will collect the highest mean contribution level.

2will not be recorded in the model since the mean contribution levels of brunette Caucasian and minority female is the same.

06

Hypothesis testing for β’s

To check whether1 is different from 0, theH0:1whileH0:10. Since the value of the p-value is given to be less than 0.01 which indicates that the value of1is not zero. However, for2the value is coming to be positive but not significantly different from 0 since the p-value is greater than 0.10 thus the value of2will be 0.

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