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Pre-Test

The probability of a high school basketball team winning any game is 58%. The team is in a six-game tournament, and the games are played independently. Let [tex]\( X \)[/tex] represent the number of games the team might win.

What are the mean and standard deviation of [tex]\( X \)[/tex]?

A. [tex]\( \mu_X = 2.52, \sigma_X = 2.14 \)[/tex]
B. [tex]\( \mu_X = 3.48, \sigma_X = 1.21 \)[/tex]
C. [tex]\( \mu_X = 3.48, \sigma_X = 1.46 \)[/tex]
D. [tex]\( \mu_X = 5, \sigma_X = 1.46 \)[/tex]


Sagot :

To find the mean and standard deviation of the number of games won by the basketball team, let's define the parameters for our problem:

- The probability of winning any given game, [tex]\( p \)[/tex], is 0.58.
- The number of games played, [tex]\( n \)[/tex], is 6.
- The number of games won, [tex]\( X \)[/tex], follows a binomial distribution with parameters [tex]\( n \)[/tex] and [tex]\( p \)[/tex].

The mean [tex]\((\mu_x)\)[/tex] of a binomial distribution can be calculated using the formula:
[tex]\[ \mu_x = n \cdot p \][/tex]

Substituting the given values:
[tex]\[ \mu_x = 6 \cdot 0.58 \][/tex]
[tex]\[ \mu_x = 3.48 \][/tex]

The standard deviation [tex]\((\sigma_x)\)[/tex] of a binomial distribution can be calculated using the formula:
[tex]\[ \sigma_x = \sqrt{n \cdot p \cdot (1 - p)} \][/tex]

Again, substituting the given values:
[tex]\[ \sigma_x = \sqrt{6 \cdot 0.58 \cdot (1 - 0.58)} \][/tex]
[tex]\[ \sigma_x \approx 1.21 \][/tex]

So, we find that the mean number of games won, [tex]\(\mu_x\)[/tex], is approximately 3.48, and the standard deviation, [tex]\(\sigma_x\)[/tex], is approximately 1.21.

Therefore, the correct answer is:
[tex]\(\mu_x = 3.48, \sigma_x = 1.21\)[/tex]