RESEARCH METHODOLOGY

STATISTICAL TECHNIQUES AND TOOLS

REGRESSION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If Linear regression model perfectly first i.e., train error is zero, then
A
Test error is also always zero
B
Test error is non zero
C
Couldn’t comment on Test error
D
Test error is equal to Train error
Explanation: 

Detailed explanation-1: -Explanation: Test Error depends on the test data. If the Test data is an exact representation of train data then test error is always zero.

Detailed explanation-2: -One of the assumptions of linear regression is that the errors have mean zero, conditional on the covariates. This implies that the unconditional or marginal mean of the errors have mean zero. One might be tempted to check whether this latter property is true using the sample data.

Detailed explanation-3: -Within a linear regression model tracking a stock’s price over time, the error term is the difference between the expected price at a particular time and the price that was actually observed.

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