Video Transcript
Four measurements are shown on the
scale below. The actual value being measured is
15.0. What scientific words would be used
to describe the red arrows? (A) Accurate but not precise, (B)
accurate and precise, (C) not accurate and not precise, (D) not accurate but
precise.
To answer the question, we need to
determine how to describe the red arrows using the terms “accurate” and
“precise.”
Accuracy describes how close a
scientific measurement is to a true or accepted value. Accuracy applies to scientific
measurements as well as everyday tasks. For example, you can fire an arrow
accurately by hitting the center of the target. You can pour a drink accurately by
pouring it into a cup rather than missing and getting it on the table. You can even give an accurate
account of a journey by recalling the correct details or an inaccurate one by
missing or changing facts.
In the question, the actual value
being measured, or the true value, is 15.0. We can see that the red arrows are
close to 15.0, so we can describe the red arrows as accurate. In contrast, the blue arrows are
not close to 15.0, so these arrows can be described as inaccurate. As the red arrows are accurate, we
can eliminate answer choices (C) and (D).
Precision describes how close
measurements are to each other. You can fire arrows precisely to
get them to hit the same area of a target, even if that isn’t the part you aimed
for. Sometimes, scientific equipment
gives readings that may be precise but are consistently inaccurate. And this means we should calibrate
it. The red arrows in the question are
close to each other, so we can describe them as precise. In contrast, the blue arrows are
not close to each other, so we can describe them as imprecise.
In conclusion, we can describe the
red arrows as both accurate and precise, answer choice (B).
