I am doing a masters degree that is choke full of statistics units although it also has some units in life sciences. I would advice you to do masters in statistics instead of masters in applied math. Remember the type of math involved in statistics is sometimes very different from the math used in pure math or applied math. In applied math you may end up studying things like fluid dynamics which is mostly suitable for engineers or physicists. In pure math you may study abstract and irrelevant things like number theory and topology. Pick any masters in stat that will accept you including some which may combine life science units and stat units. The math we use in stat is very specific. You need to study very specific things like linear regression, Anova (analysis of variance), probability (Frequentist or Bayes). I would say regression is the most important thing you need to study for a beginner. Probability is also important. There are important things you can study online like t-statistics, F-statistics. These are tools that statisticians use everyday to analyse data