When we write vectors as matrices, we tend to write an $n$-dimensional vector vector as $n \times 1$ column matrix. We emphasize that the gradient vector is defined only for scalar-valued functions. For vector valued functions, we will stick with viewing the derivative as a matrix.
Gloomy Addiction Relapse Statistics. Drug and alcohol rehab statistics show that the percentage of people who will relapse after a period recovery ranges from 50% to 90%. This is a frightening statistic and it is often used as justification for those who wish to carry on with their addiction.
Among those who do, the new data suggest that 40 percent will die in the year after discharge and 60 percent will survive. Bottom line: For the person who suffers cardiac arrest in the hospital, the odds of being among the one-year survivors works out to about 12 percent, or one in eight.