问题如下图：
选项：
A. 
B. 
C. 
解释：
老师能解释下这道题怎么算的吗？我只会讲义那种常规题，是不是这些都需要掌握呀？
菲菲_品职助教 · 2018年08月31日
同学你好，这道题考的是均值假设检验中同一总体中两组数据的均值比较。第一组数据的df=60-1=59，第二组数据的df=60-1=59，加起来总的df=118，所以B错误。通过查表可以知道，在α=0.05（双尾），df=118时，临界值为1.98，所以C错误，A正确。
如果想要数量拿到A最好是都掌握哦，但是不作为重点，如果实在记不住可以选择性放弃。但是在有充足的复习准备时间的情况下要尽量把这些知识点都掌握哦~
加油~
chyje2007 · 2018年08月31日
那这道题 z stastic值能算出来吗？怎么算的呀
菲菲_品职助教 · 2018年08月31日
这道题用的是T检验哦，这里不会要求t值的计算，一般都是计算机直接给出结果的呢。
chyje2007 · 2018年09月01日
如果用的t检验，那么1.98值就需要查表得到吧？而不是z检验背的那几个值了
菲菲_品职助教 · 2018年09月01日
是的。不过考试的时候关于查表的都会给数据的，所以只需要了解一下每张表怎么查即可。
NO.PZ2018062016000140问题如下ring the table below, the memonthly return of X Inx in the first five years have been fferent ththe mereturn in the seconfive years.Let the μ1 stanfor the population mereturn for the year1 through ye5 anμ2 stanfor the population mereturn for the ye6 through ye10, the following hypothese: H0: μ1 – μ2 = 0 versus Hμ1 – μ2 ≠ 0 Assume ththe significant level is 0.05Whiof the following options is most accurate?A.The null hypothesis will rejecteif t -1.98 or t 1.98. B.The t-test h119 grees of freem. C.The rejection points are ±1.658.A is correct. The two samples are awn from two fferent time perio, so they are inpennt samples. The population variances cassumeto equal. Unr all consirations, the t-test h60+60-2=118 grees of freem.For a two-tailetest, the significant level of 0.05, the rejection points are ±1.980, so we will rejethe null if t -1.980 or t 1.980.谢谢谢。。。。。。。
NO.PZ2018062016000140 问题如下 ring the table below, the memonthly return of X Inx in the first five years have been fferent ththe mereturn in the seconfive years.Let the μ1 stanfor the population mereturn for the year1 through ye5 anμ2 stanfor the population mereturn for the ye6 through ye10, the following hypothese: H0: μ1 – μ2 = 0 versus Hμ1 – μ2 ≠ 0 Assume ththe significant level is 0.05Whiof the following options is most accurate? A.The null hypothesis will rejecteif t -1.98 or t 1.98. B.The t-test h119 grees of freem. C.The rejection points are ±1.658. A is correct. The two samples are awn from two fferent time perio, so they are inpennt samples. The population variances cassumeto equal. Unr all consirations, the t-test h60+60-2=118 grees of freem.For a two-tailetest, the significant level of 0.05, the rejection points are ±1.980, so we will rejethe null if t -1.980 or t 1.980. 为什么是t分布呢
NO.PZ2018062016000140 问题如下 ring the table below, the memonthly return of X Inx in the first five years have been fferent ththe mereturn in the seconfive years.Let the μ1 stanfor the population mereturn for the year1 through ye5 anμ2 stanfor the population mereturn for the ye6 through ye10, the following hypothese: H0: μ1 – μ2 = 0 versus Hμ1 – μ2 ≠ 0 Assume ththe significant level is 0.05Whiof the following options is most accurate? A.The null hypothesis will rejecteif t -1.98 or t 1.98. B.The t-test h119 grees of freem. C.The rejection points are ±1.658. A is correct. The two samples are awn from two fferent time perio, so they are inpennt samples. The population variances cassumeto equal. Unr all consirations, the t-test h60+60-2=118 grees of freem.For a two-tailetest, the significant level of 0.05, the rejection points are ±1.980, so we will rejethe null if t -1.980 or t 1.980. 由于拒绝原假设的原则为|t-statistic|＞|criticvalue|，可知A正确。請問|t-statistic|為多少？這題如何計算，謝謝，
NO.PZ2018062016000140问题如下ring the table below, the memonthly return of X Inx in the first five years have been fferent ththe mereturn in the seconfive years.Let the μ1 stanfor the population mereturn for the year1 through ye5 anμ2 stanfor the population mereturn for the ye6 through ye10, the following hypothese: H0: μ1 – μ2 = 0 versus Hμ1 – μ2 ≠ 0 Assume ththe significant level is 0.05Whiof the following options is most accurate?A.The null hypothesis will rejecteif t -1.98 or t 1.98. B.The t-test h119 grees of freem. C.The rejection points are ±1.658.A is correct. The two samples are awn from two fferent time perio, so they are inpennt samples. The population variances cassumeto equal. Unr all consirations, the t-test h60+60-2=118 grees of freem.For a two-tailetest, the significant level of 0.05, the rejection points are ±1.980, so we will rejethe null if t -1.980 or t 1.980.可以詳細講一下做題思路嗎
NO.PZ2018062016000140 The t-test h119 grees of freem. The rejection points are ±1.658. A is correct. The two samples are awn from two fferent time perio, so they are inpennt samples. The population variances cassumeto equal. Unr all consirations, the t-test h60+60-2=118 grees of freem.For a two-tailetest, the significant level of 0.05, the rejection points are ±1.980, so we will rejethe null if t1.980. 为什么是T分布不是Z分布呢 从题干哪里可以判断哇