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PROBLEM

High-rent district: The mean monthly rent for a one-bedroom apartment without a doorman in Manhattan is \(\) 2557.Assumethestandarddeviationis. Assume the standard deviation is $ 486$. A real estate firm samples 86 apartments. Use Excel.
Part: 0/50 / 5 \square
Part 1 of 5
(a) What is the probability that the sample mean rent is greater than \(\) 2627$ ? Round the answer to at least four decimal places.
The probability that the sample mean rent is greater than \(\) 2627is is \square$ .

STEP 1

1. The sample size is 86 apartments.
2. The population mean (μ\mu) is $2557.
3. The population standard deviation (σ\sigma) is $486.
4. The sample mean (xˉ\bar{x}) we are comparing to is $2627.
5. The distribution of sample means is approximately normal due to the Central Limit Theorem.

STEP 2

1. Calculate the standard error of the mean.
2. Calculate the z-score for the sample mean of $2627.
3. Use Excel to find the probability corresponding to the z-score.
4. Interpret the result to find the probability that the sample mean is greater than $2627.

STEP 3

Calculate the standard error of the mean (SEM) using the formula:
SEM=σn \text{SEM} = \frac{\sigma}{\sqrt{n}} where σ=486\sigma = 486 and n=86n = 86.
SEM=4868652.42 \text{SEM} = \frac{486}{\sqrt{86}} \approx 52.42

STEP 4

Calculate the z-score using the formula:
z=xˉμSEM z = \frac{\bar{x} - \mu}{\text{SEM}} where xˉ=2627\bar{x} = 2627, μ=2557\mu = 2557, and SEM52.42\text{SEM} \approx 52.42.
z=2627255752.421.336 z = \frac{2627 - 2557}{52.42} \approx 1.336

STEP 5

Use Excel to find the probability corresponding to the z-score. In Excel, use the formula:
=1 - NORM.S.DIST(1.336, TRUE) \text{=1 - NORM.S.DIST(1.336, TRUE)} This gives the probability that the sample mean is greater than $2627.

SOLUTION

Interpret the Excel result. The probability that the sample mean rent is greater than $2627 is approximately:
0.0909 \boxed{0.0909}

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