Math Problem Statement
The large population of 5,000 students take a practice test. The population mean is 140 correct questions, standard deviation is 80. What size samples should a researcher get to distribution of means of them samples with standard deviation of 10
Solution
To determine the sample size () that results in a sampling distribution of the means with a standard deviation of 10, we need to use the formula for the standard error of the mean:
Where:
- is the population standard deviation (80 in this case).
- is the sample size.
- The standard error of the mean is the desired standard deviation for the sampling distribution of the means (10 in this case).
We can rearrange this equation to solve for :
Now, solve for :
-
Multiply both sides of the equation by :
-
Divide both sides by 10:
-
Square both sides to eliminate the square root:
Thus, the researcher should collect samples of 64 students to achieve a distribution of sample means with a standard deviation of 10.
Would you like further explanation or additional details?
Here are 5 related questions for further exploration:
- What is the relationship between sample size and standard error of the mean?
- How does the central limit theorem apply to the sampling distribution of the mean?
- How would the required sample size change if the desired standard deviation was 5 instead of 10?
- What is the effect of increasing the population standard deviation on the sample size needed?
- How does increasing the sample size affect the accuracy of estimating the population mean?
Tip: A larger sample size reduces the variability of the sample mean, making it a better estimate of the population mean.
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Math Problem Analysis
Mathematical Concepts
Statistics
Sampling Distribution
Standard Error of the Mean
Formulas
Standard Error of the Mean = σ / √n
Theorems
Central Limit Theorem
Suitable Grade Level
Grades 11-12 and Undergraduate
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