How will I identify the level of significance and how will i determine the statistical test(hypothesis testing?
The level of significance should be given in the problem. In most simple cases such as this, 0.05 is used. Test: One sample Z test of the mean — one-tailed (Note that we are using the normal distribution instead of the student distribution because the standard deviation of the population is given and the sample size is >30) H0: mean battery life <= 40 HA: mean > 40 Level of significance = 0.05 Critical Z value = 1.645 (from a standard normal table) Test statistic Z = (45-40)/sqrt(36) = 5/6 = 0.83 Since the test statistic (0.83) does not exceed the critical value (1.645), we cannot reject the null hypothesis; we cannot support the hypothesis that mean batter life exceeds 40 hours. (And in this case, p ~= 0.2967, well above the 0.
