A study was conducted to test whether there is a difference in two methods for measuring vitamin B12 in red blood cells. Blood samples were taken from seven healthy adults. Then for each blood sample, the B12 level was determined using methods A and B. The results are shown below: 1 Method A 277 253 Are the two samples independent? Give your reasons? Calculate the mean difference and standard deviation difference between methods A and B. Test at 10% signicant level whether there are differences between the two methods A and B regarding measuring the B12 level in red blood cells