Do the data provide significant evidence, at the 4.6% level, that the population mean time for patients diagnosed with schizophrenia exceeds the population mean time for normal individuals by more than 20 points? SHOW YOUR WORK AND WRITE NEATLY. READ CARFULLY AT THE PROBLEM

16 Cognitive impairment of schizophrenics. A study of the differences in cognitive function between normal individuals and patients diagnosed with schizophrenia was published in the American Journal of Psychiatry (Apr. 2010). The total time (in minutes) a subject spent on the Trail Making Test (a standard psychological test) was used as a measure of cognitive function. The researchers theorize that the mean time on the Trail Making Test for schizophrenics will be larger than the corresponding mean for normal subjects. The data for independent random samples of 41 schizophrenics and 49 normal individuals yielded the following results: Based on Perez-Iglesias, R., et al. "White matter integrity and cognitive impairment in first-episode psychosis" American Journal of Psychiatry, Vol. 167, No. 4,Apr. 2010 (Table 1)