Directions: Identify the Rejection Region or Critical Region. battery that enables the user to use the phone for 78 hours. A sample of 50 mobile phones was checked by a customer aroup and these turned...

Extracted text: Directions: Identify the Rejection Region or Critical Region. battery that enables the user to use the phone for 78 hours. A sample of 50 mobile phones was checked by a customer aroup and these turned out to have an average of 74.3 hours with a standard deviation of 6 7 hours, If a significance level of 0.10 is acceptable, is there ample evidence to prove that the true mean period of continued cellphone usage is actually less than 78 hours without recharging? PROBLEM 2. The population variance is assumed to be unknown. A cellular phone manufacturer savs that its newly released phone has a battery that enables the user to use the phone for 68 hours. A sample of 25 mobile phones was checked by a customer group and these turned out to have an average of 67.4 hours with a standard deviation of 3.2 hours. If a significance level of 0.10 is acceptable, is there ample evidence to prove that the true mean period of continued mobile phone usage is actually less than 68 hours without recharging?