MM 207 WU Sample Size Impact on A Population Parameter Questions – Description
Sample statistics, such as the sample mean or the sample proportion, can be used to estimate a population parameter (such as the population mean or the population proportion). For example, you can estimate the true mean weight of all full-term, newborn babies in the entire world by collecting a sample and using that sample to generate a 95% confidence interval.
Because the sample is typically a relatively small portion of the entire population, errors will have to be considered. Using a sample to create a range or interval of values that estimates a population parameter is called a “confidence interval.”
Post 1: Initial Response
After completing your readings for this unit, think about and share your response to the following questions:
Offer at least two examples of a population parameter that you cannot calculate, but that you can estimate. Some examples might be the true percentage of the number of bass in Lake Erie or the mean hours of sleep per night for all U.S. college students. In your own words, why do you think it is impossible to know the actual value of any population parameter?
A sample can be used to estimate a population parameter. How does the sample size affect the estimate?
To estimate a population parameter (such as the population mean or population proportion) using a confidence interval first requires one to calculate the margin of error, E. The value of the margin of error, E, can be calculated using the appropriate formula. The formula depends on whether one is estimating a mean or estimating a proportion.
The Margin of Error, E, for a 95% confidence interval for means is: ?=1.96?? where s is the sample standard deviation and n is the sample size.
Invent a quantitative variable, such as age, weight, exam score, etc. Thinking about that variable, create a small set of data (30 data values) to describe that variable. Use Excel to calculate the sample mean of your data and the sample standard deviation. If you create 30 values, the sample size is 30. Then, calculate the margin of error.
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