determine which of the matrices are exchange matrices. For those that are exchange matrices, find a nonnegative price vector that satisfies equation (1).

What is Statistics Data collection: is collected by performing statistical experiment o 2 designs Controlled experiment Observational studies Ex. A new drug is discovered. How should an experiment be designed to test its effectiveness o We divide the subjects at random into two groups. One will receive the treatment and the other will not. The results will be compared. o The group that receive treatment is treatment group. o The group who do not receive the treatment is the control group. o The basic method to study the effectiveness of drug will be the method of comparison. o It should be double-blind; doctor don’t know which group the subjects are in and neither do the subjects. Salk Vaccine Field trial th o Study of polio (world’s most feared disease in 20 century) o Jonas Salk discovered a vaccine in 1950. o A large scale field trial was carried out among 2 million school childre3n from grade 1-3. Grade 1 and 3 were control groups. Grade 2 was treated. Grade 2: 1 million; .5 million declined, .5 million accept Grade 1 and 3: 1 million The groups were different size but they don’t have to be because the percent will be used not the actually size; the absolute value. Not all students should be vaccinated to compare