• 2022-10-27
    ‏从水平锻造机的一大批产品随机地抽取20件,测得其尺寸的平均值[img=71x22]1802f2d990b87d8.png[/img],样本方差[img=89x22]1802f2d99923d09.png[/img]假定该产品的尺寸服从正态分布[img=70x27]1802f2d9a1e67a3.png[/img],其中[img=11x18]1802f2d9aa0e999.png[/img]与[img=18x22]1802f2d9b271be2.png[/img]均未知。则[img=18x22]1802f2d9b271be2.png[/img]的置信度为0.95的置信区间为( )‏
    A: (1.056,2.207)
    B: (0.056,0.207)
    C: (0.056,1.207)
    D: (0.156,0.207)
  • 举一反三