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Answer:
The probability that the sample mean will be between 82.5 and 86 years is 0.8351.
Step-by-step explanation:
According to the Central Limit Theorem if an unknown population is selected with mean μ and standard deviation σ and appropriately huge random samples (n > 30) are selected from this population with replacement, then the distribution of the sample means will be approximately normally.
Then, the mean of the sample means is given by,
[tex]\mu_{\bar x}=\mu\\[/tex]
And the standard deviation of the sample means is given by,
[tex]\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}}[/tex]
The information provided is:
[tex]\mu=85\\\sigma=6\\n=36[/tex]
As the sample size is large enough the Central Limit Theorem can be used to approximate the sampling distribution of sample mean life expectancy (M) in the United States.
Compute the probability that the sample mean will be between 82.5 and 86 years as follows:
[tex]P(82.5<\bar X<86)=P(\frac{82.5-85}{6/\sqrt{36}}<\frac{\bar X-\mu_{\bar x}}{\sigma_{\bar x}}<\frac{86-85}{6/\sqrt{36}})\\\\=P(-2.5<Z<1)\\\\=P(Z<1)-P(Z<-2.5)\\\\=0.84134-0.00621\\\\=0.83513\\\\\approx 0.8351[/tex]
Thus, the probability that the sample mean will be between 82.5 and 86 years is 0.8351.
The probability that the sample mean will be between 82.5 and 86 years is 0.8351.
Standard deviation σ = 6
Sample size n =36
What is the central limit theorem?
The central limit theorem (CLT) states that the distribution of sample means approximates a normal distribution as the sample size gets larger, regardless of the population's distribution.
Since the sample size is significant i.e. large, so the given scenario can be treated as normally distributed as per the central limit theorem.
So, the standard deviation of sample means = σ/√n
The probability that the sample mean will be between 82.5 and 86 years:
[tex]P(82.5 < X < 86) = P(\frac{82.5-85}{\frac{6}{\sqrt{36} } } < Z < \frac{86-85}{\frac{6}{\sqrt{36} } } )[/tex]
[tex]P(-2.5 < Z < 1)=P(Z < 1)-P(Z < 2.5)[/tex]
[tex]P(-2.5 < Z < 1) =0.8413-0.0062=0.8351[/tex]
Therefore, the probability that the sample mean will be between 82.5 and 86 years is 0.8351.
To get more about the central limit theorem visit:
https://brainly.com/question/18403552
