. a model proposed for nba basketball supposes that when two teams with roughly the same record play each other, the number of points scored in a quarter by the home team minus the number scored by the visiting team is approximately a normal random variable with mean 1.5 and variance 6. in addition, the model supposes that the point differentials for the four quarters are independent. assume the model is correct. (a) what is the probability the home team wins? (b) what is the conditional probability that the home team wins, given that is is behind 5 points by the end of halftime. (c) what is the conditional probability that the home team wins, given that it is ahead by 5 points at the end of the first quarter

Respuesta :

a) The probability the home team wins is of: 0.7291 = 72.91%.

b) The conditional probability that the home team wins, given that is is behind 5 points by the end of halftime is of: 0.3409 = 34.09%.

c) The conditional probability that the home team wins, given that it is ahead by 5 points at the end of the first quarter is of: 0.9015 = 90.15%.

How to obtain probabilities using the normal distribution?

The z-score of a measure X of a variable that has mean symbolized by [tex]\mu[/tex] and standard deviation symbolized by [tex]\sigma[/tex] is obtained by the rule presented as follows:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

  • The z-score represents how many standard deviations the measure X is above or below the mean of the distribution, depending if the obtained z-score is positive or negative.
  • Using the z-score table, the p-value associated with the calculated z-score is found, and it represents the percentile of the measure X in the distribution.

The mean and the standard deviation for each quarter are given as follows:

  • Mean: 1.5.
  • Standard deviation: square root of 6 = 2.45.

Hence for each case, the mean and the standard deviation are given as follows:

  • Entire game -> Four quarters -> [tex]\mu = 6, \sigma = 9.8[/tex]
  • After halftime -> Two quarters -> [tex]\mu = 3, \sigma = 4.9[/tex]
  • After the first quarter -> Three quarters -> [tex]\mu = 4.5, \sigma = 7.35[/tex]

The probability of the home team winning is the probability of X being greater than zero for four quarters, hence it is one subtracted by the p-value of Z when X = 0, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

Z = (0 - 6)/9.8

Z = -0.61

Z = -0.61 has a p-value of 0.2709.

1 - 0.2709 = 0.7291 = 72.91%.

When the home team is down five points at the end of the halftime, the probability of winning is P(X > 5) for two quarters, hence one subtracted by the p-value of Z when X = 5 as follows:

Z = (5 - 3)/4.9

Z = 0.41

Z = 0.41 has a p-value of 0.6591.

Z =  has a p-value of 0.6591.

1 - 0.6591 = 0.3409 = 34.09%.

When the home team is up five points at the end of the first quarter, the probability of winning is P(X > -5) for three quarters, hence one subtracted by the p-value of Z when X = -5.

Z = (-5 - 4.5)/7.35

Z = -1.29

Z = -1.29 has a p-value of 0.0985.

1 - 0.0985 = 0.9015 = 90.15%.

More can be learned about the normal distribution at https://brainly.com/question/25800303

#SPJ1