Question

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In a regression analysis involving 27 observations, the following estimated regression equation was developed.

ŷ = 25.2 + 5.5x₁

For this estimated regression equation SST = 1,525 and SSE = 560.

(a)

At α = 0.05, test whether

x₁

is significant.Suppose that variables

x₂ and x₃

are added to the model and the following regression equation is obtained.

ŷ = 16.3 + 2.3x₁ + 12.1x₂ − 5.8x₃

For this estimated regression equation SST = 1,525 and SSE = 100.

(b)

Use an F test and a 0.05 level of significance to determine whether

x₂ and x₃

contribute significantly to the model.

Answer 1