Answer:
a) 0.2416
b) 0.4172
c) 0.0253
Step-by-step explanation:
Since the result of the test should be independent of the time , then the that the test number of times that test proves correct is independent of the days the river is correct .
denoting event a A=the test proves correct and B=the river is polluted
a) the test indicates pollution when
- the river is polluted and the test is correct
- the river is not polluted and the test fails
then
P(test indicates pollution)= P(A)*P(B)+ (1-P(A))*(1-P(B)) = 0.12*0.84+0.88*0.16 = 0.2416
b) according to Bayes
P(A∩B)= P(A/B)*P(B) → P(A/B)=P(A∩B)/P(B)
then
P(pollution exists/test indicates pollution)=P(A∩B)/P(B) = 0.84*0.12 / 0.2416 = 0.4172
c) since
P(test indicates no pollution)= P(A)*(1-P(B))+ (1-P(A))*P(B) = 0.84*0.88+ 0.16*0.12 = 0.7584
the rate of false positives is
P(river is polluted/test indicates no pollution) = 0.12*0.16 / 0.7584 = 0.0253
so since Mrs Jackson used 2/15 of 7/8, the amount she used is simply their product.
Answer:
540°.
Step-by-step explanation:
On a unit circle, cos θ = -1 at 180°.
However, cos θ has a period of 2π, or 360°. This means that cos θ will equal to -1 again after 2π.
To solve for the angle:
180° + 360° = 540°. This is the next angle at which cos θ = -1.
297/11 = 27
So we have 27 groups of 11 students. If there are 2 chaperones for every 11 students, then we can do:
27x2=54
There are 54 chaperones on the field trip.
Is there more option choices since the ones that are visible rent correct
Maybe upload an image of the choice rather than text since it’s unreadable
