GRE数学例题解析：统计学
<p> 新<span word="gre">gre</span>更侧重基本能力的考察真正提高考生的英语水平，与老<span word="GRE">GRE</span>比起来，虽然新<span word="gre">gre</span>数学考试难度系数增大，但是新<span word="gre">gre</span>数学最大也跑不出高三知识范围，在这里提醒考生的是，难度对我们不构成威胁，作为考生要把的强项发挥到极致，把新<span word="gre">gre</span>数学统计学部分经常考察的例题解析弄明白。</p><p> 1.<span word="mode">mode</span></p><p> 一堆数中出现频率最高的一个或几个数</p><p> <span word="e">e</span>.<span word="g">g</span>. <span word="mode">mode</span> <span word="of">of</span> 1,1,1,2,3,0,0,0,5 <span word="is">is</span> 1 <span word="and">and</span> 0</p><p> 2.<span word="range">range</span></p><p> 一堆数中最大和最小数之差 ,所以统计学上又称之为极差.</p><p> <span word="e">e</span>.<span word="g">g</span>. <span word="range">range</span> <span word="of">of</span> 1,1,2,3,5 <span word="is">is</span> 5-1=4</p><p> 3.<span word="mean">mean</span></p><p> <span word="arithmatic">arithmatic</span> <span word="mean">mean</span>: <span word="n">n</span>个数之和再除以<span word="n">n</span></p><p> <span word="geometric">geometric</span> <span word="mean">mean</span> : <span word="n">n</span>个数之积的<span word="n">n</span>次方根</p><p> 4.<span word="median">median</span></p><p> 将一堆数排序之后，正中间的一个数，</p><p> 或者中间两个数的平均数</p><p> <span word="e">e</span>.<span word="g">g</span>. <span word="median">median</span> <span word="of">of</span> 1,7,4,9,2,2,2,2,2,5,8 <span word="is">is</span> 2</p><p> <span word="median">median</span> <span word="of">of</span> 1,7,4,9,2,5 <span word="is">is</span> /2=6</p><p> 5.<span word="standard">standard</span> <span word="error">error</span></p><p> 一堆数中，每个数与平均数的差的绝对值之和，除以这堆数的个数</p><p> <span word="e">e</span>.<span word="g">g</span>. <span word="standard">standard</span> <span word="error">error</span> <span word="of">of</span> 0,2,5,7,6 <span word="is">is</span>:</p><p> /5=2.4</p><p> 6.<span word="standard">standard</span> <span word="variation">variation</span></p>
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