Give a 90% confidence interval for the mean "absolutely refractory period" for all rats of this strain when subjected to the same treatment. S7.10 Suppose that the mean "absolutely refractory period" for unpoisoned rats is known to be 1.3 milliseconds. DDT poisoning should slow nerve recovery and so increase this period. Do the data in the previous exercise give good evidence for this supposition? State H0 and Ha and do a t test. Between what levels from Table D does the P -value lie? What do you conclude from the test?