开发者:上海品职教育科技有限公司 隐私政策详情

应用版本:4.2.11(IOS)|3.2.5(安卓)APP下载

Luhunlu · 2022年02月18日

老师,请问以后这种题都是这样做吗?

NO.PZ2020010304000036

问题如下:

For the following data:

a. What is the median?

b. What is the IQR?

选项:

解释:

a. The first step is to rank order the observations.

From here, we anchor the first observation at 0% and the last at 100%, equally spacing the in-between val-ues. The divisions here will be 100/n-1 = 20%:

The median (50%) lies exactly half way between the third and fourth ranked observations. Therefore:

Median=(0.28+0.38)/2=0.33

b. This requires calculating the 25% and 75% levels.

The 25% level is 5/20 = 25% of the way between ranked observations 2 and 3. Therefore: q25% = 0.75 * 0.27 + 0.25 * 0.28 = 0.2725

Similarly, the 75% level is 75% of the way between observations 4 and 5: q75% = 0.25 * 0.38 + 0.75 * 0.43 = 0.4175

Thus, IQR = (0.2725, 0.4175).

做题思路都是默认第一个数的概率是0%,然后其余的数平分100%的概率,并按照从小到大和累计概率来排序,是这样吗?


假如这道题是11个数,那么升序排列后概率依次为0%、10%······100%,

(假如还是这些数)四分之一分位点就是:q25%=0.27*50%+0.28*50%=0.275;

或者用线性差值法来做:(x-0.27)/(0.28-0.27)=(25%-20%)/(30%-20%)


辛苦老师解答!

1 个答案

李坏_品职助教 · 2022年02月18日

嗨,从没放弃的小努力你好:


对的,就是这样。先从0到100%平分概率,从小到大排序,然后根据25%与相邻两个概率的差额,来决定差值的权重。如果是11个数,那么25%分位点就在20%和30%之间,是这两个临界点各占0.5。

----------------------------------------------
就算太阳没有迎着我们而来,我们正在朝着它而去,加油!

  • 1

    回答
  • 0

    关注
  • 444

    浏览
相关问题

NO.PZ2020010304000036问题如下For the following ta:Whis the mean? Whis the IQR?The first step is to rank orr the observations.From here, we anchor the first observation 0% anthe last 100%, equally spacing the in-between val-ues. The visions here will 100/n-1 = 20%:The me(50%) lies exactly half wbetween the thiranfourth rankeobservations. Therefore:Mean=(0.28+0.38)/2=0.33 This requires calculating the 25% an75% levels.The 25% level is 5/20 = 25% of the wbetween rankeobservations 2 an3. Therefore: q25% = 0.75 * 0.27 + 0.25 * 0.28 = 0.2725Similarly, the 75% level is 75% of the wbetween observations 4 an5: q75% = 0.25 * 0.38 + 0.75 * 0.43 = 0.4175Thus, IQR = (0.2725, 0.4175). 老师,这种方式也叫插分吗?

2024-05-13 16:04 1 · 回答

NO.PZ2020010304000036 问题如下 For the following ta:Whis the mean? Whis the IQR? The first step is to rank orr the observations.From here, we anchor the first observation 0% anthe last 100%, equally spacing the in-between val-ues. The visions here will 100/n-1 = 20%:The me(50%) lies exactly half wbetween the thiranfourth rankeobservations. Therefore:Mean=(0.28+0.38)/2=0.33 This requires calculating the 25% an75% levels.The 25% level is 5/20 = 25% of the wbetween rankeobservations 2 an3. Therefore: q25% = 0.75 * 0.27 + 0.25 * 0.28 = 0.2725Similarly, the 75% level is 75% of the wbetween observations 4 an5: q75% = 0.25 * 0.38 + 0.75 * 0.43 = 0.4175Thus, IQR = (0.2725, 0.4175). 应该怎么求?没看懂解析。

2024-02-03 15:28 2 · 回答

NO.PZ2020010304000036正常情况下不是默认取这6个数的概率相同吗,那每个数应该是100%/6,我认为第一个数应该是有概率的

2022-06-23 13:57 1 · 回答

NO.PZ2020010304000036 求分位点分母为什么是n-1?

2022-03-19 15:40 1 · 回答