Q1) Manufacturer of flashlight batteries took sample of 13 batteries from day's production and used them continuously until they failed to work.  Life lengths of batteries, in hours, until they failed were:  342, 426, 317, 545, 264, 451, 1049, 631, 512, 266, 492, 562, and 298.

 At.05 level of significance, is there evidence to propose that mean life length of the batteries manufactured by this manufacturer is more than 400 hours?   

i) No, as p-value for this test is equal to .1164

ii) Yes, as the test value 1.257 is less than critical value 1.782

iii) No, as the test value 1.257 is greater than critical value 1.115

iv) Yes, as the test value 1.257 is less than critical value 2.179