The article \"The Undrained Strength of Some Thawed Permafrost Soils\" contained

Question

The article "The Undrained Strength of Some Thawed Permafrost Soils" contained the accompanying data on the following.

y = shear strength of sandy soil (kPa)
x1 = depth (m)
x2 = water content (%)

The predicted values and residuals were computed using the estimated regression equation where x3 = x12, x4 = x22, and x5 = x1x2

(a) Use the given information to compute SSResid, SSTo, and SSRegr. (Round your answer to four decimal places if needed.)

(b) Calculate R2 for this regression model. (Round your answer to three decimal places if needed.)
R2 =  

(c) Use the value of R2 from Part (b) and a 0.05 level of significance to conduct the appropriate model utility test. (Round the answer to two decimal places.)
F =

----------------------------------------------------------------

In an experiment to investigate the performance of four different brands of spark plugs intended for use on a 125-cc motorcycle, five plugs of each brand were tested, and the number of miles (at a constant speed) until failure was observed. A partially completed ANOVA table is given.

Fill in the missing entries, and test the relevant hypotheses using a .05 level of significance. (Give the answer to two decimal places.)

SSTo =   SSResid =   SSRegr =  

Explanation / Answer

(a) SSTo= 1618.209

SSResid= 390.6386

SSRegr= 1227.571

(b)R2=SSRegr/SSTo=1227.571/1618.209=0.7586

(c) F=(R2*(n-k))/((1-R2)*(k-1))=(0.7586*(14-6))/(1-0.7586)*(6-1))=5.03 with ((k-1)=5,(n-k)=8)

critical F (0.05,5,8)=3.69, is less than calcuated F, so R2 is significant

Treatement SS=Total SS- Error SS

there are total 4 brands(treatment) , so treatment df=4-1=3

each brand is replicated 5 times so toal df=5*4-1=19

MS=SS/df

F=MS(treatment)/MS(error)

source df SS MS F Treatemetns 3 77643.91 25881.3 1.764098 error 16 234738 14671.13 total 19 312382

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.