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Question: Mental health of a community. An article in the Community Mental Health Journal (August 2000) used multiple regression analysis to model the level of community adjustment of clients of the Department of Mental Health and Addiction Services in Connecticut. The dependent variable, community adjustment (y), was measured quantitatively based on staff ratings of the clients.(Lower scores indicate better adjustment.) The complete model was a first-order model with 21 independent variables. The independent variables were categorized as Demographic (4 variables), Diagnostic (7 variables),Treatment (4 variables), and Community (6 variables).

  1. Write the equation of E(y) for the complete model.
  2. Give the null hypothesis for testing whether the 7Diagnostic variables contribute information for the prediction of y.
  3. Give the equation of the reduced model appropriate for the test, part b.
  4. The test, part b, resulted in a test statistic of F = 59.3 and p-value <.0001. Interpret this result in the words of the problem.

Short Answer

Expert verified

Answer

a. The equation for E(Y) for the complete model would be

Ey=0+1x1+2x2+3x3+4x4+5x5+6x6+7x7+8x8+9x9+10x10+11x11+12x12+13x13+14x14+15x15+16x16+17x17+18x18+19x19+20x20+21x21

b. The null hypothesis for testing whether the 7 Diagnostic variables contribute information for the prediction of y can be written as


H0:5=6=7=8=9=10=11=12=0.

c. Equation of the reduced model can be written as

E(y)=0+1x1+2x2+3x3+4x4+5x5+6x6+7x7.

d. The 7 diagnostic variables contribute information for the prediction of y.

Step by step solution

01

Equation of E(y) for the complete model 

a.

The independent variables were categorized as Demographic (4 variables), Diagnostic (7 variables), Treatment (4 variables), and Community (6 variables).

Here, the demographic variables are fromx1-x4, the diagnostic variables beinglocalid="1662025858306" x12-x5, treatment variables beingx13-x17, and community variables beingx18-x21.

The equation for E(Y) for the complete model would be 鈥

Ey=0+1x1+2x2+3x3+4x4+5x5+6x6+7x7+8x8+9x9+10x10+11x11+12x12+13x13+14x14+15x15+16x16+17x17+18x18+19x19+20x20+21x21

02

Hypothesis testing

b.

The null hypothesis for testing whether the 7 Diagnostic variables contribute information for the prediction of y can be written as

H0:5=6=7=8=9=10=11=12=0

03

 Step 3: Equation of the reduced model

c.

Equation of the reduced model can be written as

E(y)=0+1x1+2x2+3x3+4x4+5x5+6x6+7x7

04

Interpretation of hypothesis testing 

d.

The null hypothesis is rejected when F-statistic>Fvalues or when p-value for the test is less than 0.05. given here is that p-value for the test conducted is less than 0.0001 which is less than 0.05 indicating thatH0 is rejected. This means that the 7 diagnostic variables contribute information for the prediction of y.

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