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
131
2
1,500
142
3
750
111
4
1,500
264
5
1,250
237
6
1,750
267
7
1,500
61
8
2,000
135
9
2,000
263
10
2,000
263
11
750
125
12
1,500
76
13
2,000
77
14
750
170
15
1,000
165
16
1,000
152
17
1,000
238
18
1,750
209
19
1,250
167
20
1,750
75
a. Compute the correlation between the
wattage and heating area. Is there a direct or an indirect
relationship? (Round your answer to 4 decimal
places.)
b. Conduct a test of hypothesis to determine
if it is reasonable that the coefficient is greater than zero. Use
the 0.010 significance level. (Round intermediate
calculations and final answer to 3 decimal places.)
H0: Ļ ā¤
0; H1: Ļ > 0
Reject H0 if t >
2.552
c. 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.)
d. What heating area corresponds with a
1,500-watt heater? (Round your answers to 4 decimal
places.)
e. What is the 95% confidence interval of
heating the area if the wattage is 1,500? (Round your
answers to 4 decimal places.)
