Question

A study was conducted to determine if 2 types of car batteries lasted the same amount of time. A sample of 50 brand x batteries lasted and average of 3.5 years, with a standard deviation of 1.0 years. A sample of 40 brand y batteries lasted 3.2 years with a standard deviation of 1.5 years. Test at the 90% confidence level to determine whether or not the brands last the same amount of time. Use a two tailed test of hypothesis, and the critical value method, do not find the p-value.

Answer 1

2 solution: Given x = 3.5 years si = 1:0 yeders n Y = 3.2 years Sa S yeded SO sh2 = 40 o=0:10 test we want to Hoi 4 = Uz Hr., & lz علاج Test Statistic . t- X-4 2 2 s² ni 02 3.5-3.2 to V so +(1.52² so 40 t 0.3 1.08656 0.2761 ts 1.087 critical value Value = + toatz 2 88 + 1.662 It tata, Atr=2 Hence we do not at 10.1 los ngiect Ho car batte sies lasted the same The amount of time