The level of monoamine oxidase (MAO) activity in blood platelets (nm/mg protein/h) was determined for each individual in a sample of 43 chronic schizophrenics, resulting in and , as well as for 45 normal subjects, resulting in and . Does this data strongly suggest that true average MAO activity for normal subjects is more than twice the activity level for schizophrenics?

Derive a test procedure and carry out the test using

[Hint: H0 and Ha here have a different form from the three standard cases. Let m1 and m2 refer to true average MAO activity for schizophrenics and normal subjects, respectively, and consider the parameter .

Write H0 and Ha in terms of u, estimate u, and derive

(“Reduced Monoamine Oxidase Activity in Blood Platelets from Schizophrenic Patients,” Nature, July 28, 1972:

225–226).]