During the winter months, heating bills can be expensive. A contractor claims that installing a new brand of insulation will considerably lower your heating bill (which was $205 last month). After conducting the test (assuming the data were provided). you find that the results are significant at the 5% level. You may also conclude: .a. the test would also be significant at the 10% level. b. the test would also be significant at the 1% level. c. both of the above. d. none of the above.

The correct option is  a

Step-by-step explanation:

Generally the null hypothesis is  rejected (that the result is significant ) when the p-value is less that the the level of significance

Now from the question when the the level of significance was 5% the p-value was less than the level of significance so also when the level of significance is   10% the p-value will be less than the level of significance hence null hypothesis will also be rejected at this level(that is the result will also  be significant at the level of significance )