Respuesta :
Using the normal distribution and the central limit theorem, it is found that the probability that the mean plant height is less than 9.5 cm is of 0.9388.
Normal Probability Distribution
In a normal distribution 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]
- It 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.
- 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 mean and the standard deviation are given, respectively, by [tex]\mu = 9.31, \sigma = 0.55[/tex].
For samples of n = 20, the standard error is given by:
[tex]s = \frac{\sigma}{\sqrt{n}}[/tex]
[tex]s = \frac{0.55}{\sqrt{20}}[/tex]
s = 0.123.
The probability that the mean plant height is less than 9.5 cm is the p-value of Z when X = 9.5, hence:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem:
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{9.5 - 9.31}{0.123}[/tex]
Z = 1.54.
Z = 1.54 has a p-value of 0.9388.
Hence the probability that the mean plant height is less than 9.5 cm is of 0.9388.
To learn more about the normal distribution and the central limit theorem, you can check https://brainly.com/question/24663213
