Two cyclists start at the same point and travel in opposite directions. One cyclist travels 6 / km h faster than the other. If t
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Answer:
The positive predictive value ≈ 30.012%
Step-by-step explanation:
(a) The given percentage of the people in the region that have the disease, P(D) = 6% = 0.06
The percentage people correctly identified as having the disease by the standard diagnostic test = 91%
The percentage of people incorrectly identified as having the disease by the standard diagnostic test, P(T + |H) = 8%
Therefore, the sensitivity of the test, P(T + |D) = 0.91
The specificity of the test, P(T - |H) = 1 - 0.08 = 0.92
Therefore, the probability that a person is healthy, P(H) = 1 - 0.06 = 0.94
Therefore, in a population of 1,000 people, 60 people have the disease, with a sensitivity of 91%, the test will correctly pic 0.91×66 = 60.06 people correctly with the disease and 0.91 × 940 = 855.4 people without the disease
The number of non-diseased that test positive by the test is 0.08 × 1000 = 80 people which are false positives
Therefore, the number of diseased diagnosed as negative is 0.08 × 60 = 4.8
Therefore, we have;
The positive predictive value = Diseased +ve/(Diseased +ve + Non-diseased +ve)
Therefore;
The positive predictive value = 60.06/(60.06 + 140.06) × 100 ≈ 30.012%
Answer:
Step-by-step explanation:
step 1
Find the area of the plate
The area of a circle is given by the formula
we have
---> the radius is half the diameter
substitute
step 2
Find the area of the square napkin folded (is a half of the area of the square napkin)
we know that
The diagonal of the square is the same that the diameter of the plate
Applying Pythagorean theorem
where
b is the length side of the square
we have
substitute
solve for b^2
-----> is the area of the square
Divide by 2
step 3
Find the area of the space on the plate that is NOT covered by the napkin
we know that
The area of the space on the plate that is NOT covered by the napkin, is equal to subtract the area of the square napkin folded (is a half of the area of the square napkin) from the area of the plate
so
simplify