Use the table to answer the question.

Color
Shape Red Yellow TOTAL
Circle 12 18 30
Triangle 20 30 50
Total 32 48 80
Let event A represent the P(yellow) and let event B represent the P(yellow|triangle) . Are they independent? Explain.

(1 point)
Responses

Yes, because P(A|B)=P(A).
Yes, because upper P left parenthesis upper A vertical bar upper B right parenthesis equals upper P left parenthesis upper A right parenthesis .

Yes, because P(A)=P(B).
Yes, because upper P left parenthesis upper A right parenthesis equals upper P left parenthesis upper B right parenthesis .

No, because both events do not include triangles.
No, because both events do not include triangles.

No, because both events do not include yellow.

1 answer

To determine if events A and B are independent, we can use the definition of independence of events. Two events A and B are independent if:

\[ P(A | B) = P(A) \]

Where:

  • \( P(A) \) is the probability of event A occurring.
  • \( P(B) \) is the probability of event B occurring.
  • \( P(A | B) \) is the probability of event A occurring given that event B has occurred.

First, we calculate \( P(A) \) and \( P(B) \).

  1. Calculate P(A) (Probability of yellow):

    • Total yellow = 48
    • Total observations = 80
    • So, \( P(A) = \frac{\text{Total yellow}}{\text{Total observations}} = \frac{48}{80} = 0.6 \).
  2. Calculate P(B) (Probability of yellow given triangle):

    • Total triangles = 50
    • Yellow triangles = 30
    • So, \( P(B) = P(\text{yellow | triangle}) = \frac{\text{Yellow triangles}}{\text{Total triangles}} = \frac{30}{50} = 0.6 \).
  3. Calculate P(A | B) (Probability of yellow given triangle):

    • As calculated above, since event B considers only triangles and the probability of selecting a yellow triangle is already calculated as \( P(B) = 0.6 \).

Now we need to check if \( P(A | B) = P(A) \).

Since we have \( P(A | B) \) calculated from the triangle row and it results in the same value as \( P(A) \), the values of both are:

  • \( P(A) = 0.6 \)
  • \( P(A | B) = 0.6 \)

Thus, we can conclude:

Yes, because \( P(A | B) = P(A) \).

So, the correct response would be:

Yes, because \( P(A | B) = P(A) \).