Question

A consumer buying cooperative tested the effective heating area of 20 different electric space heaters with different wattages. Here are the results.

heater	Wattage		Area
1	1,500		74
2	1,000		237
3	1,500		50
4	1,500		133
5	1,500		89
6	2,000		285
7	1,500		251
8	1,250		291
9	1,000		121
10	1,750		148
11	1,750		111
12	1,000		254
13	1,750		103
14	1,000		299
15	1,250		115
16	1,000		200
17	1,750		106
18	1,250		74
19	1,500		64
20	1,250		64

1. Compute the correlation between the wattage and heating area. Is there a direct or an indirect relationship? (Round your answer to 4 decimal places.) 2. Conduct a test of hypothesis to determine if it is reasonable that the coefficient is greater than zero. Use the 0.100 significance level. (Round intermediate calculations and final answer to 3 decimal places.) H₀: ρ ≤ 0; H₁: ρ > 0 Reject H₀ if t > 1.330 3. Develop the regression equation for effective heating based on wattage. (Negative value should be indicated by a minus sign. Round your answers to 3 decimal places.) 4.  Which heater looks like the “best buy” based on the size of the residual? (Round residual value to 3 decimal places.)

Answer 1