The water department checks the city water supply on a regular basis for contaminants such as xylenes. the water department take
s 200 samples and estimates that the concentration of xylenes in your drinking water is 3.5 ppb (parts per billion), with a standard deviation of 0.2 ppb.
assuming the samples were random and unbiased, how much confidence can you have in this data?
assuming the samples were random and unbiased, how much confidence can you have in this data?
1 answer:
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Answer:
Step-by-step explanation:
Please refer to the attached diagram. (Apologies if the shading or resolution is a bit off.)
So, we want to find θ.
Since we formed a right triangle, we can use right triangle ratios.
We know the measure of the adjacent side to θ and the hypotenuse.
Therefore, we will use the cosine ratio:
The adjacent side is 2 and the hypotenuse is 15. By substitution:
Now, we will take the inverse cosine of both sides. So:
Use a calculator. Hence:
The angle between the ground and the ladder is about 82.34°.
