设总体 sim N(mu ,(sigma )^2), 若σ^2已知,总体均值μ的置信度为 https:/img.cdnjtzy.com/zyb_0487be8cec6c71f3a81e9931cdf3f01d.jpg-a 的置信区间为-|||-(overline (X)-lambda dfrac (sigma )(sqrt {n)},overline (X)+lambda dfrac (sigma )(sqrt {n)}), 则 lambda = __A.设总体 sim N(mu ,(sigma )^2), 若σ^2已知,总体均值μ的置信度为 https:/img.cdnjtzy.com/zyb_7debb36b144578f652f1654a43569b56.jpg-a 的置信区间为-|||-(overline (X)-lambda dfrac (sigma )(sqrt {n)},overline (X)+lambda dfrac (sigma )(sqrt {n)}), 则 lambda = __B.设总体 sim N(mu ,(sigma )^2), 若σ^2已知,总体均值μ的置信度为 https:/img.cdnjtzy.com/zyb_c81e8f9ef1737eedf52949263fb44c1e.jpg-a 的置信区间为-|||-(overline (X)-lambda dfrac (sigma )(sqrt {n)},overline (X)+lambda dfrac (sigma )(sqrt {n)}), 则 lambda = __C.设总体 sim N(mu ,(sigma )^2), 若σ^2已知,总体均值μ的置信度为 https:/img.cdnjtzy.com/zyb_a19478961c992eab88d6e5bbc67636b3.jpg-a 的置信区间为-|||-(overline (X)-lambda dfrac (sigma )(sqrt {n)},overline (X)+lambda dfrac (sigma )(sqrt {n)}), 则 lambda = __D.设总体 sim N(mu ,(sigma )^2), 若σ^2已知,总体均值μ的置信度为 https:/img.cdnjtzy.com/zyb_520ec7ec56d5733ae537f24247f61df9.jpg-a 的置信区间为-|||-(overline (X)-lambda dfrac (sigma )(sqrt {n)},overline (X)+lambda dfrac (sigma )(sqrt {n)}), 则 lambda = __