<em>Answer</em>
<em><u>Given</u></em>
<em>the relative frequency tables in the figure below (Note: the tables are not in the same order as in the problem statement)</em>
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<em><u>Find</u></em>
<em>which table is best suited to answer the question</em>
<em />
<em>A) the percentage of home viewers who prefer to watch horror movies </em>
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<em>B) the percentage of people surveyed who prefer to watch comedy movies at home </em>
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<em>C) the percentage of viewers with a preference for drama who watch at the theater </em>
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<em><u>Solution</u></em>
<em>The figure shows the best choices for answering A, B, and C.</em>
<em />
<em>table 2 is best for A (it is normalized by viewing location)</em>
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<em>table 3 is best for B (it is normalized over the whole sample)</em>
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<em>table 1 is best for C (it is normalized by genre)</em>
Answer:
The probability of testing positive for one is 0.20.
The probability of testing negative for one sample is (1-0.2)=0.8.
We only save time when all five are negative, which has a probability of 0.8^5=0.32768.
This means that the expected number of tests is
combined sample tests negative = 1 with probability 0.32768
combined sample tests positive = 1+5 retests = 6 with probability 0.67232
Expected number of tests
=Σ nipi / n
=(1*0.32768+6*0.67232)/5 [divide by 5 because we tested 5 samples]
= 0.87232 < 1
So yes, there is a saving.
Note: In practice, all medical tests are not absolute, i.e. they give false-positives(α) and false-negatives (β). The ratios 1-α and 1-β are respectively measures of specificity and sensitivity.
These two parameters complicate the simplistic evaluation above.
The graph and the equation show the same
D. Plug the first number into “n” to get the second number
Answer:
Compounds contains atoms from different elements. The elements are bounded chemically. H20, stands from a hydrogen atom and two oxygen atoms bonded together. These are two different elements and therefore the combination of H20 fits the definition for a compound.