Toaster Oven An Appliance Manufacturer Claims to Have Developed a New Toaster

Short Answer

Toaster Oven
An appliance manufacturer claims to have developed a new toaster oven that consumes an average of no more than 250 W.From previous studies,it is believed that power consumption for toaster ovens is normally distributed with a standard deviation of 18 W.A consumer group suspects the actual average is more than 250 W.They take a sample of 20 toaster ovens and calculate the average consumption to be 260 W. ​ ​
-{Toaster Oven Narrative} Calculate the p-value of the test.