Q1) Cell phone producer claims that its phone will last for more than eight hours of continuous talk time when battery is fully charged. To test this claim a sample of n = 18 phones were tested. Results illustrated a sample mean of 8.2 hours and sample standard deviation of 0.4 hours. Conduct hypothesis test using a 0.05 level of significance and find out whether or not company's claim is supported.

Q2)  If hypothesis test for single population variance is to be conducted by using significance level of to 0.10, a sample size of n = 16, and test is a one-tailed upper-tail test, the critical value is:        

i) z  =  1.28.

ii) t =  1.345.

iii) x²= 22.3071.

iv) x²= 24.9958.