题目1单选题
来自正态总体<img src="https://tihai-oss-cloud.itihey.com/img/d8cfc62eabce9fc22349afae4c96dfa6.png">,容量为400的简单随机样本,样本均值为45,则未知参数<img src="https://tihai-oss-cloud.itihey.com/img/ed1f4d3c386f168f6dd71edf78235307.png">的置信度为0.95的置信区间是<img src="https://tihai-oss-cloud.itihey.com/img/bbcf92bcc8fd13a7ef2490bc8c98df33.png"> ( )A. [44,46]B. [44.804,45.196]C. [44.8355,45.1645]D. [44.9,45.1]