Question

1)Annual high temperatures in a certain location have been tracked for several years. Let X represent the year and Y the high temperature. Based on the data shown below, calculate the regression line (each value to two decimal places).

y = _____________ x + ________________

x	y
3	10.42
4	10.96
5	13.8
6	17.14
7	16.98
8	21.22
9	23.96
10	23.9
11	27.14
12	30.28
13	30.22
14	34.06
15	37.1
16	36.74
17	41.08
18	41.62

2) Annual high temperatures in a certain location have been tracked for several years. Let X represent the year and Y the high temperature. Based on the data shown below, calculate the correlation coefficient (to three decimal places) between X and Y. Use your calculator!

x	y
4	22.68
5	21.8
6	23.42
7	24.24
8	25.86
9	28.68
10	32.9
11	31.92
12	36.24
13	36.26
14	36.18
15	41.4
16	43.02

r=

3)Recently a community college offered a 2-credit course to help students with math anxiety. At the beginning of the course, each student took a 30-question survey (called MARS-S); the higher the score, the more anxiety experienced by the student. The nine students remaining in the class took the same survey at the end of the course. The before and after scores for each of the nine students who completed the course are shown below.

student	before	after
1	72	69
2	66	52
3	83	71
4	97	85
5	95	61
6	78	45
7	95	56
8	52	43
9	93	62

Compute the correlation between before and after scores for these students. (Assume the correlation conditions have been satisfied and round your answer to the nearest 0.001.)

Answer 1

Answer 1:

The equation of the regression line is:

y = 3.21 + 2.17*x

Answer 2:

The correlation coefficient is:

r = 0.980

Answer 3:

The correlation coefficient is:

r = 0.588