STAT 2500 Final Exam Study Guide
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Questions and Answers

What is the computed sum of squares for error (SSE)?

  • 239.5 (correct)
  • 3997.41
  • 12
  • None of the above

    • How many degrees of freedom for treatment (DFT) are there in the analysis?

  • 4
  • 1
  • 3
  • 2 (correct)

    • What is the calculated mean squares of treatment (MST)?

  • 500.7
  • 1332.9 (correct)
  • 499.8
  • 2000

    • What is the significance level used in the paramedics' test regarding call numbers?

    <p>0.01</p> Signup and view all the answers

    What statistic is used to determine if the mean number of calls is significantly different among shifts?

    <p>F-statistic</p> Signup and view all the answers

    Based on the analysis results, what conclusion can the paramedics draw regarding shift call numbers?

    <p>The mean numbers of calls differ among the shifts.</p> Signup and view all the answers

    What method did paramedics use to collect data on call numbers?

    <p>Observations over a week</p> Signup and view all the answers

    If the calculated F-statistic results in a p-value lower than 0.01, what would be the appropriate conclusion?

    <p>Reject the null hypothesis.</p> Signup and view all the answers

    What is the null hypothesis regarding the proportions of women and men who chose the state of the economy as their biggest concern?

    <p>The proportions of women and men choosing the economy are equal.</p> Signup and view all the answers

    In hypothesis testing, what does a significance level of α = 0.05 represent?

    <p>There is a 5% chance of making a Type I error.</p> Signup and view all the answers

    If a manufacturer claims that their cordless telephone has a greater calling range than a competitor, what statistical test should be used?

    <p>Two-sample t-test.</p> Signup and view all the answers

    What is the correct formula to compute the test statistic when comparing two means assuming equal variances?

    <p>$t = \frac{(\bar{x}_1 - \bar{x}_2)}{s_p \sqrt{\frac{1}{n_1} + \frac{1}{n_2}}}$</p> Signup and view all the answers

    In order to find the degrees of freedom for error (DFE) in a study involving three drug formulations with 30 volunteers, what is the correct calculation?

    <p>27</p> Signup and view all the answers

    What is the critical value for an ANOVA test with DFE = 12 and DFT = 15 at α = 0.05?

    <p>2.93</p> Signup and view all the answers

    What conclusion can be drawn if the p-value is less than 0.05 in hypothesis testing?

    <p>Reject the null hypothesis and accept the alternative.</p> Signup and view all the answers

    When constructing a 95% confidence interval for the difference between two population proportions, which value is crucial?

    <p>The standard error of the difference.</p> Signup and view all the answers

    What can be concluded about the call volume across different shifts?

    <p>The mean call volume differs between shifts.</p> Signup and view all the answers

    What does a statistically significant correlation coefficient imply for the study of bone density?

    <p>There is a clear relationship between age and bone density.</p> Signup and view all the answers

    Why is it inappropriate to use the regression line for predictions if the correlation coefficient is not significant?

    <p>The regression line could lead to random predictions.</p> Signup and view all the answers

    What factor is necessary for determining if the correlation coefficient, r, is significant at the 0.05 level?

    <p>The p-value associated with <em>r</em> must be less than 0.05.</p> Signup and view all the answers

    When analyzing the regression line for predicting GPA, what does a high number of parking tickets indicate?

    <p>There may be a negative relationship affecting GPA.</p> Signup and view all the answers

    What type of analysis is used to assess the relationship between the number of parking tickets and student GPA?

    <p>Regression analysis.</p> Signup and view all the answers

    What characteristic of a study sample enhances its reliability in statistical analysis?

    <p>It should consist of a large and random selection.</p> Signup and view all the answers

    How can practitioners ensure the validity of using a correlation coefficient to make predictions?

    <p>By ensuring the correlation coefficient is statistically significant.</p> Signup and view all the answers

    What does a negative slope of the regression line indicate about the correlation coefficient?

    <p>The correlation coefficient must be negative.</p> Signup and view all the answers

    Which of the following describes the possible correlation if the correlation coefficient is $r = 0$?

    <p>There is no linear relationship between the two variables.</p> Signup and view all the answers

    In the context of a scatterplot for flight data, which variable is considered the independent variable?

    <p>Distance (1000s of miles)</p> Signup and view all the answers

    If the regression line can effectively predict GPA based on the number of parking tickets, what might the coefficient of determination indicate?

    <p>Strong explanatory power of the model.</p> Signup and view all the answers

    What can be concluded if the relationship between Distance and Time in a scatterplot is described as linear and strong?

    <p>Changes in Distance predict changes in Time effectively.</p> Signup and view all the answers

    What does it mean if the regression model has a low residual value for the first student?

    <p>The model accurately predicts the student's GPA.</p> Signup and view all the answers

    Which statement best describes a linear, positive relationship in a scatterplot?

    <p>As one variable increases, the other variable also increases.</p> Signup and view all the answers

    Which of the following best explains why a regression line is useful?

    <p>It provides a method of prediction based on one variable.</p> Signup and view all the answers

    Study Notes

    STAT 2500 Final Exam Study Guide

    • Exam 1: Covers hypothesis testing regarding proportions, means, and variances. Includes computing test statistics, p-values, and making conclusions.

    • Exam 2: Focuses on ANOVA tests. Includes calculating sums of squares (SSE), degrees of freedom (DFT, DFE), mean squares (MST), F-statistics, and determining statistical significance.

    • Exam 3: Examines correlation and regression analysis. Includes scatterplots, correlation coefficients, linear regression models, estimations, coefficients of determination, and identifying the dependent variable.

    • General Statistical Concepts: This material emphasizes understanding different types of relationships between variables (linear, non-linear, positive, negative, strong, weak), the identification of appropriate statistical tests, and the interpretation of results in the context of real-world applications. Questions may test your ability to calculate and interpret statistics relevant to these concepts.

    • Gallup Polls: Frequent examples in the study guide involve Gallup polls. The examples demonstrate hypothesis tests about proportions involving women and men and their concerns about the state of the economy.

    • Hypothesis Testing: Critical concept in the exam. Includes stating null and alternative hypotheses, choosing test statistics, calculating p-values, and concluding about population parameters.

    Specific Exam Questions

    • Question 1: Hypothesis test about proportion of women and men concerned about the economy.

    • Question 2: Hypothesis test comparing the calling range of cordless phones using sample statistics. Assumes equal population variances.

    • Question 3: 95% confidence interval for the difference in proportions concerning the economy's impact.

    • Question 4: Calculating the critical value of an ANOVA test given alpha, degrees of freedom for error and treatment.

    • Question 5: Determining the degrees of freedom for error in an experiment with three drug formulations and 30 volunteers.

    • Question 6: An ANOVA table is provided. Required to calculate sums of squares for error, degrees of freedom for treatment, mean squares for treatment, the F-Statistic, and significance.

    • Question 7: Analyzing call data from paramedics to determine if there are differences in the mean number of calls received during different shifts (morning, afternoon, night).

    • Question 8: Determining if the correlation coefficient for bone density and age (a given dataset) is statistically significant at the 0.05 level.

    • Question 9: Regression analysis involving GPA and parking tickets for college students; required to find the regression line, estimate a GPA, calculate the coefficient of determination, and find the residual of the first student.

    • Question 10: True/False question about the relationship between the slope and the correlation coefficient in a regression.

    • Question 11: Relationship between distance (in thousands of miles) and time (in hours) in a scatterplot context. Determining whether the relationship is linear, non-linear, positive, negative or strong weak.

    • Question 12: Identifying the dependent variable in a scatterplot (where time/distance might be used).

    • Question 13: Understanding what a correlation coefficient of r=0 signifies.

    • Question 14: Determining the correlation coefficient (r) from a scatterplot to assess the strength of the relationship.

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    STAT 2500 Study Guide Final Exam Fall PDF

    Description

    Prepare for your STAT 2500 final exam with this comprehensive study guide covering key concepts. The guide includes topics like hypothesis testing, ANOVA, correlation, and regression analysis. Gain a solid understanding of statistical relationships and test interpretations for real-world applications.

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