1) Actuary 1) Mathematical statistician 2) Mathematician 
A statistician is someone who works with theoretical or applied statistics. The profession exists in both the private and public sectors. It is common to combine statistical knowledge with expertise in other subjects. ==Nature of the work== According to the United States Bureau of Labor Statistics, as of 2010, 25,100 jobs were classified as statis...
• (n.) One versed in statistics; one who collects and classifies facts for statistics.
A person who specialises in or works with statistics
Stat`is·ti'cian noun [ Confer French statisticien .] One versed in statistics; one who collects and classifies facts for statistics. 
[n] - a mathematician who specializes in statistics 2. [n] - someone versed in the collection and interpretation of numerical data (especially someone who uses statistics to calculate insurance premiums)
Someone who works on trial results to find out whether they have happened by chance, or whether one treatment is really better than another. Also work out how many people are needed to take part in a trial and put them into groups at random.
noun a mathematician who specializes in statisticsactuary noun someone versed in the collection and interpretation of numerical data (especially someone who uses statistics to calculate insurance premiums)
an expert in or compiler of statistics.