Question

Given are five observations for two variables,  and . Use Table 2 of Appendix B.

	1	2	3	4	5
	3	7	5	11	14

Round your answers to two decimal places.

a. Using the following equation:

Sy*=s*SQRT(1/n + (x*-xbar)^2/Sigma(xi-xbar)^2)

Estimate the standard deviation of ^y* when x=4 .

b. Using the following expression:

^y*+-(t a/2)Sy*

Develop a  confidence interval for the expected value of y when x=4 .
to

c. Using the following equation:

S pred=s*sqrt(1+1/n+(x*-xbar)^2/sigma(xi-xbar)2

Estimate the standard deviation of an individual value of 7 when x=4.

d. Using the following expression:

^y*=t a/2(S pred)

Develop a  prediction interval for y when x=4

Answer 1

a)

std deviation =1.11

b)

95% CI =7.06 ; 14.14 (try 7.07 ; 14.13 this comes wrong)

c)

std deviation =2.32

d)

95% PI =3.22 ; 17.98