Answer: the probability that a person who tested positive actually has TB is 0.64
Step-by-step explanation:
lets say
T : has tuberculosis
+ : test results +ve
- : test result is -ve
so given that
P(+ITc) = 0.008
P(-ITc) = 0.15
P(T) = 50/3000 = 1/60
P(Tc) = 1 - P(T) = 1 - 1/60 = 59/60
Now required probability
= P(TI+)
P(T∩+) / P(+)
= P(T) × P(+IT) / [[P(T) × P(+IT)] + [(P(Tc) × P(+ITc)]
= P(T) × {1-P(-IT)] / [[P(T) × [1-P(-IT)] + [(P(Tc) × P(+ITc)]
WE SUBSTITUTE
= { 1/60 × (1-0.15) } / [1/60 × (1 - 0.15)] + [(59/60) × 0.008]
= (0.0167 × 0.85) / [(0.0167 × 0.85) + (0.9833 × 0.008)]
= 0.01417 / 0.02206
= 0.6423 ≈ 0.64
∴ the probability that a person who tested positive actually has TB is 0.64
Answer:
Surface area = 663π in².
Volume = (676/3)π in² ≈ 225.33 π in²
Explanation:
1) We know the radius and the lateral area.
2) With the radius you can find the areas of the top and the bottom.
For that, you use the formula:
area of the top = area of the bottom = π r²
∴ π (13 in)² = 169π in² (each)
3) Then, the surface area is the sum of the lateral area and the two bases (top and bottom)
surface area = lateral area + bottom area + top area = 325π in² + 2×169π in² = 663π in².
3) You can also find the height of the cylinder.
Use the formula: lateral area = 2π r h
∴ h = lateral area / [2 π r]
⇒ h = 325 π / [ 2π (13) ] = 12.5 in
4) With the height you can find the volume.
Use the formula: V = (4/3) π r³
∴ V = (4/3) π (13 in)³ = (676/3)π in² ≈ 225.33 π in²
