Answer :
Answer:
0.3085 = 30.85% probability that the mean years of experience from the sample of 4 is greater than 3.5 years.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution
When the distribution is normal, we use 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 normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
Distribution of years of experience:
Mean 3, so [tex]\mu = 3[/tex]
Standard deviation 2, so [tex]\sigma = 2[/tex]
Sample of 4:
[tex]n = 4, s = \frac{2}{\sqrt{4}} = 1[/tex]
What is the probability that the mean years of experience from the sample of 4 is greater than 3.5?
1 subtracted by the pvalue of Z when X = 3.5. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{3.5 - 3}{1}[/tex]
[tex]Z = 0.5[/tex]
[tex]Z = 0.5[/tex] has a pvalue of 0.6915
1 - 0.6915 = 0.3085
0.3085 = 30.85% probability that the mean years of experience from the sample of 4 is greater than 3.5 years.
Answer:
We cannot calculate this probability because the sampling distribution n ot normal
Step-by-step explanation: Khan academy