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	1,560		231
2	670		63
3	1,530		222
4	1,280		150
5	1,220		200
6	1,280		203
7	940		118
8	1,970		314
9	1,000		111
10	1,460		197
11	1,340		103
12	530		63
13	590		89
14	1,410		229
15	2,090		235
16	1,590		230
17	810		72
18	1,440		185
19	1,150		194
20	500		32

1. Compute the correlation between the wattage and heating area. Is there a direct or an indirect relationship? (Negative value should be indicated by a minus sign. Round your answer to 3 decimal places.)

2. Conduct a test of hypothesis to determine if it is reasonable that the coefficient is greater than zero. Use the 0.01 significance level. (Negative value should be indicated by a minus sign. Round intermediate calculations and final answer to 3 decimal places.)

H₀: ρ ≤ 0; H₁: ρ > 0 Reject H₀ if t > 2.5524

t=

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.)

The regression equation is: Area = + Wattage

4. Which heater looks like the “best buy” based on the size of the residual? (Negative value should be indicated by a minus sign. Round residual value to 2 decimal places.)

Answer 1