Using the normal distribution, it is found that the minimum average wait time is of 192 seconds.
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Normal Probability Distribution
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
- The Z-score measures how many standard deviations the measure is from the mean.
- After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.
In this problem:
- Mean of 185 seconds, thus [tex]\mu = 185[/tex].
- Standard deviation of 11 seconds, thus [tex]\sigma = 11[/tex].
- The top 25% is at least the 100 - 25 = 75th percentile, which is X when Z has a p-value of 0.75, so X when Z = 0.675.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]0.675 = \frac{X - 185}{11}[/tex]
[tex]X - 185 = 11(0.675)[/tex]
[tex]X = 192[/tex]
The minimum wait time is of 192 seconds.
A similar problem is given at https://brainly.com/question/7001627
