准确性和准确性

How do professional basketball players improve their shooting accuracy?
::专业篮球运动员如何提高射击准确性?

Basketball is one of those sports where you need to hit the target.  A football field goal kicker might have room for some deviation from a straight line – for college and pro football there is an 18 foot 6 inch space for the ball to go through.  In basketball, the basket is only 18 inches across and the ball is a little less than 10 inches across – not much room for error .  The ball has to be on target in order to go into the basket and score.
::篮球是那些你需要击中目标的运动之一。 足球场踢球手可能有偏离直线的空间 — — 大学和足球运动员有18英尺6英寸的球空间。 在篮球中,篮子只穿过18英寸,球面小于10英寸 — — 没有太多错误空间。 球必须瞄准目标才能进入篮子并得分。

Accuracy and Precision
::准确性和准确性

In everyday speech, the terms accuracy and precision are frequently used interchangeably.  However, their scientific meanings are quite different.  Accuracy is a measure of how close a measurement is to the correct or accepted value of the quantity being measured.  Precision is a measure of how close a series of measurements are to one another.  Precise measurements are highly reproducible, even if the measurements are not near the correct value.
::在日常演讲中,准确性和精确性经常被互换使用,然而,它们的科学含义却大相径庭。准确性是测量所测量数量是否接近正确或可接受的数值的尺度。精确度是测量一系列测量之间如何接近的尺度。精确度是高度可复制的,即使测量值并不接近正确值。

Darts thrown at a dartboard are helpful in illustrating accuracy and precision
::向飞镖板投掷飞镖有助于说明准确性和准确性

Assume that three darts are thrown at the dartboard, with the bulls-eye representing the true, or accepted, value of what is being measured.  A dart that hits the bulls-eye is highly accurate, whereas a dart that lands far away from the bulls-eye displays poor accuracy.  Figure demonstrates four possible outcomes.
::假设有三只飞镖被扔到飞镖板上,公牛眼代表所测量物体的真实价值或公认价值。 击中公牛眼的飞镖非常精确,而远离公牛眼的飞镖则显示不准确。 图显示四种可能的结果。

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1. The darts have landed far from each other and far from the bulls-eye.  This grouping demonstrates measurements that are neither accurate, nor precise.
   ::飞镖相距遥远,距离公牛眼很远。 这种组合显示测量结果既不准确也不准确。
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2. The darts are close to one another, but far from the bulls-eye.  This grouping demonstrates measurements that are precise, but not accurate.  In a laboratory situation, high precision with low accuracy often results from a systematic error.  Either the measurer makes the same mistake repeatedly or the measuring tool is somehow flawed.  A poorly calibrated balance may give the same mass reading every time, but it will be far from the true mass of the object.
   ::飞镖彼此相近, 但距离公牛眼很远。 这种组合显示测量精确, 但并不准确。 在实验室中, 精确度低的高度往往来自系统性错误。 测量器要么反复犯同样的错误, 要么测量工具有一定的缺陷 。 差错的平衡可能每次都给出相同的质量读数, 但与对象的真实质量相去甚远 。
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3. The darts are not grouped very near to each other, but are generally centered around the bulls-eye.  This demonstrates poor precision, but fairly high accuracy.  This situation is not desirable in a lab situation because the “high” accuracy may simply be random chance and not a true indicator of good measuring skill.
   ::飞镖并不非常接近对方,而是一般集中在公牛眼周围。 这表明精确度低,但准确度高。 这种情况在实验室中并不可取,因为“ 高度”精确度可能只是随机的,而不是衡量能力良好的真正指标。
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4. The darts are grouped together and have hit the bulls-eye.  This demonstrates high precision and high accuracy.  Scientists always strive to maximize both in their measurements.
   ::飞镖被组合在一起,撞击了公牛眼,这显示了高度精确和高度精确。 科学家们总是努力在测量中实现最大化。

How is your accuracy and precision? Try out your skills with this simulation: 
::你的精确度和精确度如何?

Summary
::摘要

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• Accuracy is a measure of how close a measurement is to the correct or accepted value of the quantity being measured.
  ::准确性是衡量测量量与所测量数量的正确值或公认值有多接近的尺度。
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• Precision is a measure of how close a series of measurements are to one another.
  ::精确度量是衡量一系列测量结果彼此之间如何接近的尺度。

Review
::回顾

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1. Define accuracy.
   ::界定准确性。
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2. Define precision.
   ::界定精确度。
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3. What can be said about the reproducibility of precise values?
   ::准确值的可复制性如何?