![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
[单选题]
某船装货前测得平均吃水为7.10m, TPC=22t/cm ;装货后测得的平均吃水为7.55m, TPC=23.5t/cm;若假定装货期间船上的油水等重量不变,则装货量估计为()t
A.990
B.1058
C.1024
D.1048
![](https://static.youtibao.com/asksite/comm/h5/images/m_q_a.png)
C、1024
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
A.990
B.1058
C.1024
D.1048
C、1024
A.5.79
B.5.62
C.6.27
D.5
用甲醛法测得某铵盐中氮的质量分数为5.15%、5.32%、5.22%、5.25%。其平均值为______,标准偏差(s)为______,平均值的标准偏差为______,含氮量在置信度为95%时的置信区间为______。(
已知t0.05,3=3.18。)
A.z
B.t
C.卡方
D.D
A.70.8mm
B.129.8mm
C.141.6mm
D.188.8mm
E.413mm