A survey by the Ministry of Health found that only 15 of the 300 myopic students had the correct pen-holding posture. From this, I think that the biggest cause of myopia is the wrong posture of holding the pen. How many percent is the error rate of holding a pen?
卫生部一项调查结果发现，在300名近视学生中仅有15人的握笔姿势是正确的．由此想到近视眼的最大成因是错误的握笔姿势．握笔姿势的错误率高达百分之几？
<gadget id="calculator">300 - 15</gadget>
<output>285</output>

<gadget id="calculator">285 / 300</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(19/20) * 1</gadget>
<output>19/20 = around 0.95</output>

<result>19/20 = around 0.95</result>