Northeastern Big State University claims that the average annual cost of textbooks for students is less than 235 Thus the relevant hypotheses are Ho 235 vs H 235 The campus newspaper wants to verify these and sought the help of a statistics professor Using a random sample of 64 students a sample mean of 264 and a sample standard deviation of 211 have been computed Based on this sample data the professor concluded that the null hypothesis cannot be rejected What does this mean No meaningful inferences can be drawn because the distribution of population is unknown Confidence intervals are too narrow and computations have to be redone with a larger sample size Chance variation is an unlikely explanation for the discrepancy between the value in null hypothesis 235 and what is observed 264 most likely the true average is not 235 Results clearly indicate that sample mean 264 is higher than the hypothesized value 235 Hence Professor s conclusion is wrong the null hypothesis should be rejected It might very well be that 235 there is no evidence to dispute this Chance variation is the most likely explanation for the discrepancy between the average value in null hypothesis 235 and average value observed in the sample 264