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How do you plug numbers into the rearranged Bayes formula shown at the end?

Substitute the given numerical values into the rearranged formula P(B|A) = P(B)PP(B)P(A|B)/P(A). For example, if P(B)=1/21P(B) = 1/21, P(A|B) = 4/104/10, and P(A)=24/210P(A) = 24/210, the calculation is (1/21∗4/101/21 * 4/10) / (24/21024/210). Multiplying the numerator gives 4/2104/210, and dividing by 24/21024/210 yields 4/244/24, which simplifies to 1/61/6 or approximately 0.1667.

Conditions

  • The formula used is the rearranged Bayes identity for P(B|A).
  • The given probabilities must be consistent with the formula's assumptions (e.g., P(A)>0P(A) > 0).

Reasoning, step by step

  1. Identify the rearranged formula: P(B|A) = P(B)PP(B)P(A|B)/P(A).
  2. Substitute the given values: P(B)=1/21P(B) = 1/21, P(A|B) = 4/104/10, P(A)=24/210P(A) = 24/210.
  3. Multiply the terms in the numerator: (1/211/21) * (4/104/10) = 4/2104/210.
  4. Divide the result by the denominator: (4/2104/210) / (24/21024/210).
  5. Simplify the fraction: 4/24=1/64/24 = 1/6 ≈ 0.1667.

Example

The screen supplies P(B)=1/21P(B)=1/21, P(A|B)=4/104/10 and P(A)=24/210P(A)=24/210. Our arithmetic continuation gives P(B|A)=1/61/6≈0.1667; this simplified result is derived here rather than displayed in the source.

Common misconceptions

  • Assuming the video explicitly states the simplified decimal value aloud or on screen; the source only provides the initial fractions and the formula structure.

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Answers are generated from source material and independently checked. Consult the original video or creator if something is unclear.