Question

$1{,}000$ 个家庭的年收入从 $8200 到 $98000 不等。由于错误，最高收入在电脑中被输入为 $980000。错误数据的平均数与实际数据的平均数相差多少？

The annual incomes of $1{,}000$ families range from $8200 to $98,000. In error, the largest income was entered on the computer as $980,000. The difference between the mean of the incorrect data and the mean of the actual data is

$882

$980

$1078

$482000

$482,000

$882000

$882,000

答案：A

知识点：平均数

难度评级：1060

解答：

只有一个数据被改错。错误总和比实际总和多 $\$980{,}000 - \$98{,}000 = \$882{,}000$ 。

这多出的金额分摊到 $1000$ 个家庭上，平均数相差 $\dfrac{\$882{,}000}{1000} = \$882$ 。

所以正确答案是 A。

Only one entry changed. The incorrect total exceeds the actual total by $\$980{,}000 - \$98{,}000 = \$882{,}000.$

Since this extra amount is spread over $1000$ families, the means differ by $\dfrac{\$882{,}000}{1000} = \$882.$

Thus, the correct answer is B .

1990 AMC 8 第 20 题

答案：A

难度评级：1060

解答：

其他年份的第 20 题