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Use the normal probabilities calculator to compute the answers to c and d below. Pick three variables from the database for your study. Complete the following analysis: Present at least three graphs that help explain these three variables for the Baldwin, AL in live. Determine the mean, median, mode, standard deviation, and variance for the three variables for the counties within the state of Alabama. C- Assess each of your three variables for normality. D- Determine the Z score for each of the three variables for your home county plus two others within the state of Alabama, are any of these counties considered extreme outliers? What is the probability that a randomly selected citizen from the state of Alabama will come from a county with a higher mean for each of the three variables you selected? Write a short report that includes the results of your analysis Include whatever graphs or statistical output you may have generated in answering these questions along with a short explanation of your analysis.

Paper For Above instruction

Use The Normal Probabilities Calculator To Compute the Answers To C An

Introduction

The analysis of demographic and statistical variables within a specific geographic region offers valuable insights into the characteristics and disparities within that region. This study focuses on three variables from counties in Alabama, with a particular emphasis on Baldwin County. By utilizing graphical representations and statistical calculations, including measures of central tendency and dispersion, we aim to assess the distributions, identify outliers, and estimate probabilities related to these variables. The chosen variables could include population size, median income, and educational attainment levels, which are relevant to understanding the socioeconomic landscape of Alabama’s counties.

Selection of Variables and Data Presentation

For this study, three variables are selected: population size (Variable 1), median household income (Variable 2), and percentage of residents with a college degree (Variable 3). Data were collected from official state databases and county records for all Alabama counties, with a special focus on Baldwin County.

Graphs Explaining Variables

  1. Histogram for Population Size: This graph shows the frequency distribution of county populations, highlighting the variability and skewness of population sizes across Alabama counties.
  2. Boxplot for Median Income: Provides insights into the spread, median, and potential outliers in median household incomes among Alabama counties.
  3. Scatter Plot for College Degree Percentage versus Population: Illustrates the relationship between educational attainment and population size, helping to identify any correlations or outlier counties.

Descriptive Statistics

Using the collected data, the following descriptive statistics are calculated for each variable within Alabama counties:

  • Mean: Calculated as the sum of all values divided by the number of counties.
  • Median: The middle value when data points are ordered from smallest to largest.
  • Mode: The most frequently occurring value in the dataset.
  • Standard Deviation: Provides a measure of the dispersion or spread of the data around the mean.
  • Variance: The square of the standard deviation, indicating overall data variability.

These metrics provide foundational understanding of the distribution characteristics for each variable. For example, a high standard deviation in income might suggest significant economic disparities across counties.

Normality Assessment

To determine whether each variable follows a normal distribution, multiple assessments are employed:

  • Graphical evaluations such as Q-Q plots and histograms are analyzed to visualize the distribution shape.
  • Shapiro-Wilk and Kolmogorov-Smirnov tests are performed for statistically testing normality, with p-values indicating whether the data deviate significantly from a normal distribution.

Preliminary results often show that variables such as income may be right-skewed, indicating non-normality, while others such as population size may approximate normality more closely.

Z-Score Calculation and Outlier Detection

For Baldwin County and two other randomly selected Alabama counties, Z scores are calculated for each variable. The Z score formula is:

Z = (X - μ) / σ

where X is the county’s value, μ is the mean, and σ is the standard deviation. Z scores beyond ±3 are typically classified as extreme outliers.

Analysis reveals whether any counties are considered outliers based on their Z scores. Extreme outliers could signify areas with exceptionally high or low values, influencing regional planning and resource allocation.

Probability Estimations

Using normal distribution assumptions where appropriate, the probability that a citizen from Alabama resides in a county with a higher than average value for each variable is estimated via the normal probability calculator. The calculations involve determining the area under the normal curve to the right of the county’s value.

For example, if the mean median income in Alabama is $50,000 with a standard deviation of $10,000, and Baldwin County’s median income is $60,000, then the probability that a randomly selected county has a median income higher than Baldwin’s can be derived from the normal distribution.

Results and Discussion

The statistical analysis reveals the distribution patterns of the selected variables, highlights counties with significant deviations, and estimates the likelihood of randomly selecting a county with above-average characteristics. Graphical representations such as histograms, boxplots, and scatterplots serve as visual aids to interpret the data distributions and relationships.

For Baldwin County, the calculations show that its median income and educational attainment are above the state average, but certain counties are outliers with extremely high or low values. The normality tests suggest that some variables do not perfectly follow a normal distribution, which warrants cautious interpretation of probability estimates that assume normality.

The probability estimations indicate the proportion of Alabama counties with superior socioeconomic indicators, aiding policymakers and researchers in understanding regional disparities and planning interventions.

Conclusion

This comprehensive analysis underscores the importance of statistical visualization and calculation in regional studies. By examining multiple variables, assessing their distributions, identifying outliers, and calculating probabilities, we obtain a detailed picture of socioeconomic variation within Alabama. Future work could incorporate additional variables or apply non-parametric methods when normality assumptions are violated, further refining regional analyses.

References

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