Question

A study was carried out to relate yarn tenacity (y, in g/tex) to yarn count (x1, in tex), percentage polyester (x2), first nozzle pressure (x3, in kg/cm2), and second nozzle pressure (x4, in kg/cm2). The estimate of the constant term in the corresponding multiple regression equation was 6.128. The estimated coefficients for the four predictors were
−0.081, 0.115, 0.256, and −0.215,
respectively, and the coefficient of multiple determination was 0.945.

Answer 1

(a) Assuming that the sample size was n = 25, state and test the appropriate hypotheses to decide whether the fitted model specifies a useful linear relationship between the dependent variable and at least one of the four model predictors. (Use α = 0.001.)
State the appropriate hypotheses.

State the rejection region and compute the test statistic value. Round your answers to two decimal places.
rejection region f ≥
test statistic f =

State the conclusion in the problem context.

(b) Again using n = 25, calculate the value of adjusted R2.

(c) Calculate a 99% confidence interval for true mean yarn tenacity when yarn count is 16.8, yarn contains 40% polyester, first nozzle pressure is 3, and second nozzle pressure is 6 if the estimated standard deviation of predicted tenacity under these circumstances is 0.35

Answer 2

I have all my work done just want to make sure it's correct.

Answer 3

@AloneS

Answer 4

@wio