Statistics Problem About Sample Size
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3. The equation for determining necessary sample size (n) for confidence intervals about the mean is:
n = [z · s / E]2
Remember that the z-score corresponds to the level of confidence (if confidence is higher, the z-score is higher).
a. If we double our confidence level, what happens (numerically) to the sample size?
b. If we cut our margin of error (E) in half, what happens (numerically) to the sample size?
c. What size sample would you need to have 0 margin of error (i.e. E = 0)?
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This solution provides assistance with statistics problems such as finding sample size based on the confidence level and margin of error.
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a. If we double our confidence level, what happens (numerically) to the sample size?
Solution: Note that if confidence is higher, the z-score is higher. So, if we double our ...
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Recent Feedback
- "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
- "excellent work"
- "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
- "Thank you"
- "Thank you very much for your valuable time and assistance!"
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