The T-Score Formula. The t-score is a fraction. The numerator is the sample's mean minus mean of the group you are comparing the sample to, and the denominator is the sample's standard deviation divided by the square root of the sample size.
If you have smoked marijuana then the drug will stay for 3 to 30 days. This is normal for the common drugs. But in the case of marijuana, this can be detected even after a month in Urine drug test marijuana. Marijuana will stay in your system for 10 days if you have been smoking occasionally.
Xanax and Klonopin (Clonazepam) usually stay in the blood for several days, but exactly how long they stays in the blood can vary. Depending on frequency and length of use, you might want to wait for 3 days before drug testing (for an infrequent user) up to 4-6 weeks for a chronic user.