Sampling Distribution of the Sample Means from an Infinite Population

In summary, the individual students' scores on a national test have a normal distribution with a mean of 18.5 and a standard deviation of 7.8. At a Trade School, 84 students took the test and if the scores at this school have the same distribution as national scores, the mean, standard deviation and variance of the sample mean for 84 students can be calculated using the formula: mean = 18.5, standard deviation = 7.8/sqrt(84), and variance = (7.8)^2/84. Additionally, assuming the population is infinite, a sample of size n is taken from a population with mean \mu and standard deviation \sigma, we can expect the sample to have mean
  • #1
bunnypatotie
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1. Individual students’ scores on a national test have a normal distribution with a mean of 18.5 and a standard deviation of 7.8. At a Trade School, 84 students took the test. If the scores at this school have the same distribution as national scores, what is the mean, standard deviation and variance of the sample mean for 84 students? Assume that in this case the population is infinite.
 
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If, out of a population large enough to be treated as infinite with mean \(\displaystyle \mu\) and standard deviation \(\displaystyle \sigma\), a sample of size n is taken we can expect the sample to have mean \(\displaystyle \mu\) and standard deviation \(\displaystyle \sigma \sqrt{n}\).
 

1. What is a sampling distribution?

A sampling distribution is a theoretical probability distribution that shows all the possible values of a statistic that can be calculated from samples of a given size from a population. It helps us understand the variability of a statistic and how likely it is to occur.

2. What is the sampling distribution of the sample means from an infinite population?

The sampling distribution of the sample means from an infinite population is a normal distribution with a mean equal to the population mean and a standard deviation equal to the population standard deviation divided by the square root of the sample size. This means that as the sample size increases, the sampling distribution approaches a normal distribution.

3. How is the sampling distribution of the sample means from an infinite population different from the sampling distribution of other statistics?

The sampling distribution of the sample means from an infinite population is unique because it follows the central limit theorem, which states that the distribution of sample means will be approximately normal regardless of the shape of the population distribution. This is not true for other statistics, such as sample proportions or sample variances.

4. Why is the sampling distribution of the sample means from an infinite population important?

The sampling distribution of the sample means from an infinite population is important because it allows us to make inferences about the population mean based on a sample. It also helps us understand the precision of our sample mean estimate and the likelihood of obtaining a certain sample mean.

5. How does the sample size affect the sampling distribution of the sample means from an infinite population?

The sample size has a direct impact on the sampling distribution of the sample means from an infinite population. As the sample size increases, the sampling distribution becomes more concentrated around the population mean, with a smaller standard deviation. This means that larger sample sizes lead to more precise estimates of the population mean.

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