题目内容
测定铁矿中铁的质量分数四次结果的平均值为56.28%,标准差为0.10% 。置信度为95%时总体平均值的置信区间(%)是已知：t (0.95,3)=3.18, t (0.95,4)=2.78
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正态分布曲线反映出__________误差分布的规律性;总体平均值m表示测量值分布的__________。在不存在系统误差的情况下, m就是__________;总体标准差s 表示测量值分布的_____________。
Read the job advertisement and then answer the questions.Post: HR OfficerOrganisation: Green AssociatesSalary: f£35,000 plus excellent benefts and progressionAre you looking to join a rapidly growing advertising agency in central I ondon? Your duties are to recruit staff at all levels across the firm. Working directly under the HR manager, you will support her in all ! projects relating to Human Resource development of the organisation: recruitment, training and career development. You will also represent the company at conferences and job fairs. The successful candidate will have good organisational skills, experience of recruitment and the ability to work to tight deadlines. Previous knowledge of the sector is not necessary, as training will be given.1 What will the HR officer be mainly responsible for?2 What else does the job involve?3 Who will he / she report to?4 What will he / she need to attend from time to time?5 What doesn't he / she have to have for this job?
在包络检波器中,当调制信号的频率增加,惰性失真加剧。
在包络检波器中,当调制信号的频率增加,负峰切割失真加剧。
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