Respuesta :
Answer:
0.31% probability that the average number of bikes rented per week, during the next 30 weeks, will be at least 510.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.
Central limit theorem:
The Central Limit Theorem estabilishes that, for a random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sample means with size n of at least 30 can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex]
In this problem, we have that:
[tex]\mu = 500, \sigma = 20, n = 30, s = \frac{20}{\sqrt{30}} = 3.65[/tex]
Find the probability that the average number of bikes rented per week, during the next 30 weeks, will be at least 510.
This is 1 subtracted by the pvalue of Z when X = 510. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{510 - 500}{3.65}[/tex]
[tex]Z = 2.74[/tex]
[tex]Z = 2.74[/tex] has a pvalue of 0.9969
1 - 0.9969 = 0.0031
0.31% probability that the average number of bikes rented per week, during the next 30 weeks, will be at least 510.
