Based on the 2017 season, the Houston Astros have a winning percentage of .623. Use the binomial model to find the probability that the Astros will win 4 of their next 6 games. P(x)=[n!x!(n−x)!]pxqn−x (1 point) Responses 12.4% 12.4% 24.7% 24.7% 32.1% 32.1% 62.3%

1 answer

To compute the probability that the Houston Astros will win exactly 4 out of their next 6 games using the binomial model, we can use the formula for the binomial probability:

\[ P(x) = \binom{n}{x} p^x (1-p)^{n-x} \]

Where:

  • \( n \) = total number of trials (games) = 6
  • \( x \) = number of successful outcomes (wins) = 4
  • \( p \) = probability of success (win rate) = 0.623
  • \( 1-p \) = probability of failure (loss rate) = 1 - 0.623 = 0.377
  1. Calculate \( \binom{n}{x} \) (the number of combinations of winning \( x \) games out of \( n \)): \[ \binom{n}{x} = \frac{n!}{x!(n-x)!} = \frac{6!}{4! \cdot 2!} = \frac{720}{24 \cdot 2} = \frac{720}{48} = 15 \]

  2. Calculate \( p^x \) (the probability of winning \( x \) games): \[ p^4 = (0.623)^4 \]

    Calculate \( 0.623^4 \): \[ 0.623^4 \approx 0.0966 \]

  3. Calculate \( (1-p)^{n-x} \) (the probability of losing \( n-x \) games): \[ (1-p)^{2} = (0.377)^2 \]

    Calculate \( 0.377^2 \): \[ 0.377^2 \approx 0.1425 \]

  4. Now, combine all parts to find \( P(4) \): \[ P(4) = \binom{6}{4} p^4 (1-p)^{2} = 15 \cdot 0.0966 \cdot 0.1425 \]

    Calculate: \[ 15 \cdot 0.0966 \cdot 0.1425 \approx 15 \cdot 0.01376 \approx 0.2064 \text{ (approximately)} \]

  5. Finally, convert to percentage: \[ P(4) \approx 0.2064 \times 100 \approx 20.64% \]

From the response options provided (12.4%, 24.7%, 32.1%, 62.3%), it seems none of them closely match the computed value of approximately 20.64%.

Given common issues in such calculations, you should carefully check for rounding and calculation steps. However, based on the computed values and approximations, the probability of the Astros winning 4 out of their next 6 games using the binomial model is approximately 20.64%, which does not align with the provided options directly.