Respuesta :
Answer:
A) 10%
Step-by-step explanation:
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. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Sam's monthly bills are normally distributed with mean 2700 and standard deviation 230.9.
This means that [tex]\mu = 2700, \sigma = 230.9[/tex]
What is the probability that his expenses will exceed his income in the following month?
Expenses above 2*1500 = $3000, which is 1 subtracted by the p-value of Z when X = 3000.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{3000 - 2700}{230.9}[/tex]
[tex]Z = 1.3[/tex]
[tex]Z = 1.3[/tex] has a p-value of 0.9032.
1 - 0.9032 = 0.0968 that is, close to 10%, and thus the correct answer is given by option A.
