新GRE数学考试的考点有很多，标准偏差和排列组合是其中的两个考点，为了帮助大家更好的掌握这两个考点，下面小编就给大家简单解析一下这两个新GRE数学的考点。
　　本文为大家介绍了新GRE数学考试中标准偏差和排列组合的相关内容,希望对大家备考新GRE数学有一定的参考作用！
　　一、新GRE考试数学考点简析之标准偏差(standard deviation)
　　standard deviation等于standard variation的平方根
　　GRE经常让你比较众数或中数与数的个数的乘积和这组数的和的大小，可以举几个极限情况的例子验证一下。还有一种题型是给你两组数的平均值，方差，比较他们的中数大小;要注意中数的大小和那两个值是没有必然联系的，无法比较。
　　二、新GRE考试数学考点简析之排列组合
　　Set
　　A set is a collection of objects or things. Each object in a set a member or element of that set.Size of a set is the number of members in the set.
　　Example:
　　The set of even numbers between 2 and 10 is of size 5:{2,4,6,8,10}.
　　The set of primes between 2 and 10 is of size 4:{2,3,5,7}.
　　Remember:
　　Each member of set A belongs to A or is in the set A.
　　A set can not have repeating member:{1,3,1,2}is not a set.
　　Rearranging the order of the members does not change the set:{1,2,3}is same as{3,2,1}.
　　Combinations
　　Number of ways we can select n objects from a group of m distinct objects is m!/(n!*(m-n)!).
　　Example:
　　Number of possible ways to pick 4 oscar nominations from a list of 50 movies is 50!/(4!*(50-4)!)=50!/(4!*46!)=50*49*48*47/24=230300.
　　Remember:
　　This does not apply if there are identical objects.
　　Permutation of Objects
　　The number of ways n distinct objects can be ordered is n!.
　　Example:
　　Number of ways 6 people can from a queue is 6!.
　　Number of ways 5 different cars can be parked in 5 parking spaces is 5!.
　　Remember:
　　This does not apply if there are identical objects or ordering does not matter.