Rarely, proton pump inhibitors (such as omeprazole) have caused vitamin B-12 deficiency. The risk is increased if they are taken every day for a long time (3 years or longer). Tell your doctor right away if you develop symptoms of vitamin B-12 deficiency (such as unusual weakness, sore tongue, or numbness/tingling of the hands/feet).
Stability reliability refers to the consistency of students' scores when a test is administered to the same students on two different occasions. Alternate-form reliability describes the consistency of students' performances on two different (hopefully equivalent) versions of the same test.
For the set of test scores, the standard deviation is the square root of 75.76, or 8.7. Remember that standard deviation needs to be interpreted within the context of the data set. If you have 100 items in a data set and the standard deviation is 20, there is a relatively large spread of values away from the mean.