Using the normal distribution and the central limit theorem, it is found that the probability is given by:
e. 0.611
Normal Probability Distribution
The z-score of a measure X of a normally distributed variable with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex] is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
- By the Central Limit Theorem, the sampling distribution of sample means of size n has standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
In this problem, the parameters are given as follows:
[tex]\mu = 50, \sigma = 10, n = 9, s = \frac{10}{\sqrt{9}} = 3.3333[/tex]
The probability that this sample mean will be between 48 and 54 is the p-value of Z when X = 54 subtracted by the p-value of Z when X = 48, hence:
X = 54:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem:
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{54 - 50}{3.3333}[/tex]
Z = 1.2
Z = 1.2 has a p-value of 0.885.
X = 48:
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{48 - 50}{3.3333}[/tex]
Z = -0.6
Z = -0.6 has a p-value of 0.274.
0.885 - 0.274 = 0.611, hence option e is correct.
More can be learned about the normal distribution and the central limit theorem at https://brainly.com/question/24663213
