Question

PLEASE BE ADVISED THIS IS A MULTI PART QUESTION A-F

Answer 1

Solution: To find the answers to the given question, we can use excel regression data analysis tool. The excel output is given below:

(a) Treating the 7-day strength as the explanatory variable, x, use technology to determine the estimate of and .

Answer: From the above outputs, we have:

(b) Compute the standard error of the estimate, .

Answer: From the above outputs we have:

(c) A normal probability plot suggests that the residuals are normally distributed. Determine .

Answer: From the above output, we have:

(d) A normal probability plot suggests that the residuals are normally distributed. Test whether a linear relation exists between 7-day strength and 28-day strength at the level of significance

Answer:

A.

Determine the P-value of this hypothesis test.

Answer: From the above outputs, we have:

What is the conclusion that can be drawn?

Answer: A. Reject H₀ and conclude that a linear relation exists between the 7-day and 28-day strength of a certain type of concrete at the level of significance

(e) Construct a 95% confidence interval about the slope of the true least-squares regression line.

Answer: From the above outputs, we have:

(f) What is the estimated mean 28-day strength of this concrete if the 7-day strength is 3000 psi?

Answer: A good estimate of the mean 28-day strength is

  

Therefore a good estimate of the mean 28-day strength is psi