1、智課網(wǎng)GRE備考資料新GRE數(shù)學(xué)考點(diǎn) 標(biāo)準(zhǔn)偏差和排列組合_GRE數(shù)學(xué) 新GRE數(shù)學(xué)考試的考點(diǎn)有很多，標(biāo)準(zhǔn)偏差和排列組合是其中的兩個(gè)考點(diǎn)，為了幫助大家更好的掌握這兩個(gè)考點(diǎn)，下面小編就給大家簡(jiǎn)單解析一下這兩個(gè)新GRE數(shù)學(xué)的考點(diǎn)。 本文為大家介紹了新GRE數(shù)學(xué)考試中標(biāo)準(zhǔn)偏差和排列組合的相關(guān)內(nèi)容,希望對(duì)大家備考新GRE數(shù)學(xué)有一定的參考作用！ 一、新GRE考試數(shù)學(xué)考點(diǎn)簡(jiǎn)析之標(biāo)準(zhǔn)偏差(standard deviation) standard deviation等于standard variation的平方根 GRE經(jīng)常讓你比較眾數(shù)或中數(shù)與數(shù)的個(gè)數(shù)的乘積和這組數(shù)的和的大小，可以舉幾個(gè)極限情況的例子驗(yàn)證一下。

2、還有一種題型是給你兩組數(shù)的平均值，方差，比較他們的中數(shù)大小;要注意中數(shù)的大小和那兩個(gè)值是沒有必然聯(lián)系的，無法比較。 二、新GRE考試數(shù)學(xué)考點(diǎn)簡(jiǎn)析之排列組合 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

3、,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:1,3,1,2is not a set. Rearranging the order of the members does not change the set:1,2,3is same as3,2,1. Combinations Number of ways we can

4、 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 d