Logarithms of head injury measures for dummies in the different stats. Among other things interest lies in whether and/or what extent amount of head injury differs between the driver’s seat the passenger’s seat. Let be the difference between the logarithms of head injury measures for driver’s side. We can model as a random sample from a normal distribution with and variance . suppose that we wish to test the null hypothesis that against the alternative that at level . there are cars represented in fig 8.10 .the test would be reject if .