confidence intervals

As its name implies, confidence intervals provide a range of values, along with a level of confidence, to serve as an estimate of some unknown population value. Since it is rare to have access to the entire population, you must frequently rely on the confidence interval of the sample to make some inference about the population of interest. Before making accurate inferences to the population, we need to fully understand how the three key components of the interval—variability in the data, sample size, and confidence level—impact the width of the interval.

For this Discussion, you will explore the relationship between these components and understand the trade-off between reducing risk in our confidence of estimates and increasing precision.

To prepare for this Discussion:

• Review      Chapters 6 and 7 of the Frankfort-Nachmias & Leon-Guerrero text and in      Chapter 7, p. 188, consider Hispanic migration and earnings and focus on      how different levels of confidence and sample size work together.
• Review      Magnusson’s web blog found in the Learning Resources to further your      visualization and understanding of confidence intervals.
• Use the      Course Guide and Assignment Help found in this week’s Learning Resources      to search for a quantitative article related to confidence intervals.
• Using the      SPSS software, General Social Survey dataset and choose a quantitative      variable that interests you.

By Day 3

Using SPSS:

1. Take a      random sample of 100.
2. Calculate      the 95% confidence interval for the variable.
3. Calculate      a 90% confidence interval.
4. Take      another random sample of 400.
5. Calculate      the 95% confidence interval for the variable.
6. Calculate      a 90% confidence interval.

Post your results and an explanation of how different levels of confidence and sample size affect the width of the confidence interval. Next, consider the statement, “Confidence intervals are underutilized” and explain what the implications might be of using or not using confidence intervals. Provide examples based on the results of your data. Also, use your research to support your findings.

Be sure to support your Main Post and Response Post with reference to the week’s Learning Resources and other scholarly evidence in APA Style.

Frankfort-Nachmias, C., & Leon-Guerrero, A. (2018). Social statistics for a diverse society (8th ed.). Thousand Oaks, CA: Sage Publications.

• Chapter 5,      “The Normal Distribution” (pp. 128-150)
• Chapter 6,      “Sampling and Sampling Distributions” (pp. 151-178)
• Chapter 7,      “Estimation” (pp. 179-201)

Wagner, W. E. (2016). Using IBM® SPSS® statistics for research methods and social science statistics (6th ed.). Thousand Oaks, CA: Sage Publications.

• Chapter 3,      “Selecting and Sampling Cases”
• Chapter 5,      “Charts and Graphs”
• Chapter      11, “Editing Output”

Magnusson, K. (n.d.). Welcome to Kristoffer Magnusson’s blog about R, Statistics, Psychology, Open Science, Data Visualization