Question

As concrete​ cures, it gains strength. The following data represent the​ 7-day and​ 28-day strength in pounds per square inch​ (psi) of a certain type of concrete.

7-Day_Strength_(psi)_-_x   28-Day_Strength_(psi)_-_y
2300   4070
3380   5020
2620   4190
3390   5220
3330   4850

(a) Treating the​ 7-day strength as the explanatory​ variable, x, use technology to determine the estimates of β0 and β1.

β0≈b0=1753.9

​ (Round to one decimal place as​ needed.)

β1≈b1=0.9707 ​

(Round to four decimal places as​ needed.)

Se=150.6

​(Round to one decimal place as​ needed.)

​(c) A normal probability plot suggests that the residuals are normally distributed. Determine sb1. Use the answer from part (b).

sb1=0.1477 

(Round to four decimal places as​ needed.)

(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

α=0.05 level of significance.

State the null and alternative hypotheses. Choose the correct answer below.

A.

H0​: β1=0

H1​: β1≠0

B.

H0​: β0=0

H1​: β0≠0

C.

H0​: β0=0

H1​: β0>0

D.

H0​: β1=0

H1​: β1>0

Answer 1

d) option A. Is correct answer