A large manufacturer of windshield wiper blades needs to estimate the mean life users of the blades can expect under typical driving conditions . 一个大型挡风玻璃雨刷厂的经理，需要估计一下在一般驾驶条件下雨刷平均使用寿命的期望值有多大。
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A woman complained to the uk ' s advertising standards authority after finding under the windscreen wiper of her car a yellow advert with black arrows at the top and bottom offering a buy - one - get - one - free membership 一名妇女在她的汽车挡风玻璃雨刷下发现一张上下两边有黑色的箭头，提供买一送一的会员资格的黄色广告单后，向英国的广告标准局提出抱怨。
