In: Math
The American Association of Individual Investors (AAII) On-Line Discount Broker Survey polls members on their experiences with electronic trades handled by discount brokers. As part of the survey, members were asked to rate their satisfaction with the trade price and the speed of execution, as well as provide an overall satisfaction rating. Possible responses (scores) were no opinion (0), unsatisfied (1), somewhat satisfied (2), satisfied (3), and very satisfied (4). For each broker, summary scores were computed by computing a weighted average of the scores provided by each respondent. A portion the survey results follow (AAII website, February 7, 2012).
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(a) Here is the summary output of multiple regression
SUMMARY OUTPUT | ||||||
Regression Statistics | ||||||
Multiple R | 0.807653 | |||||
R Square | 0.652304 | |||||
Adjusted R Square | 0.589087 | |||||
Standard Error | 0.437482 | |||||
Observations | 14 | |||||
ANOVA | ||||||
df | SS | MS | F | Significance F | ||
Regression | 2 | 3.949701 | 1.97485 | 10.31842 | 0.002996 | |
Residual | 11 | 2.105299 | 0.191391 | |||
Total | 13 | 6.055 | ||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | |
Intercept | -0.82091 | 1.016283 | -0.80775 | 0.436352 | -3.05773 | 1.415918 |
Satisfaction with Trade Price | 0.574341 | 0.248552 | 2.310748 | 0.041244 | 0.027282 | 1.121401 |
Satisfaction with Speed of Execution | 0.739116 | 0.167645 | 4.408822 | 0.001048 | 0.370132 | 1.1081 |
y^ = -0.8209 + 0.5743 x1 +0.7391 x2
Coefficient of Determintation = R2 = 0.6523
Here interpretation of Coefficient of Determination is " 65.23% of variation in Overall Satisfaction with Electronic Trades for any brokerage is explained by the variation in "Satisifaction with Trade Price" and "satisfaction in Speed of Execution".
(b) Here for variable"Satisifaction with Trade Price"
Test statistic
t = 2.3107
dF = 11 and tcritical = 2.20
so here t > tcritical so regression coefficient is significant here.
for variable "Satisfaction with Speed of Execution"
t = 4.41
t > tcritical so regression coeficient is significant here also.
(c) Here, yes as regression coefficient is around 0.5 to 0.7 range that is what we have predicted as both regresion coefficient is positive and have values between 0.5 and 1.
(d) Here estimated regression line is
y^ = -0.8209 + 0.5743 x1 +0.7391 x2
so here x1 = 3 = x2
y^ = -0.8209 + 0.5743 * 3 +0.7391 * 3 = 3.1195or 3.12
(e) Here if some possible responses that are vague is like : no opinion" Here no opinion is scored zero but it shall not be included in the sample size becuase it will drastically vary the results.