Statistics

In Professor Smith's statistics course, the correlation between students' total scores before the final exam and their final exam scores is r = 0.67. The pre-exam totals for all students in the course have a mean of 275 and a standard deviation of 26. The final exam scores have a mean of 71 and a standard deviation of 6. Professor Smith has lost Jane's final exam, so decides to predict her final exam score based on her pre-exam course total, which is 293. Use least-squares regression to predict Jane's final exam score.

Predicted Final Exam Score =

Please explain to me how to do this. My teacher does not teach this kind of stuff in class and he expects us to know this.

  1. 👍
  2. 👎
  3. 👁
  1. Pre-exam: mean = 275, sd = 26
    Final exam: mean = 71, sd = 6
    Correlation: r = 0.67

    Regression equation is in this format:
    predicted y = a + bx
    ...where a = intercept and b = slope.

    To find the equation, you need to substitute the information given in the problem into a workable formula:
    predicted y = (rSy/Sx)X - (rSy/Sx)xbar + ybar
    ...where r = correlation, Sy = sd of y, Sx = sd of x, and X is the variable in 'a + bx' equation.
    Note: xbar = mean of x; ybar = mean of y.
    I'll let you take it from here. (Once you calculate the predicted y formula, substitute 293 for x in the formula to predict Jane's final exam score.)

    1. 👍
    2. 👎
  2. what is a correlation coefficient between two variables

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Stats

    Suppose the scores of students on an exam are Normally distributed with a mean of 297 and a standard deviation of 66. Then approximately 99.7% of the exam scores lie between the numbers _____and _______such that the mean is

  2. math

    Wilson reads an article that says students who eat blueberries the morning of a test tend to have higher test scores. The article claims that eating blueberries causes an improvement in test scores. Which of the following

  3. Statistics

    A statistics professor gives a test and finds that the scores are normally distributed with a mean of 25 (out of 100) and a standard deviation of 5. She plans to curve the scores in one of two ways. 1) She could add 50 points to

  4. Statistics

    5. Scores on a recent national statistics exam were normally distributed with a mean of 80 and a standard deviation of 6. a. What is the probability that a randomly selected exam will have a score of at least 71? b. What

  1. STATISTICS

    For a 10 point quiz, the professor recorded the following scores for 8 students: 7, 8, 3, 9, 10, 6, 8, 5 What is the Mean for this set of scores?

  2. Stats, Statistics, Math

    A Statistics professor assigned 10 quizzes over the course of the semester. He wanted to see if there was a relationship between the total mark of all 10 quizzes and the final exam mark. There were 229 students who completed all

  3. Algebra

    Before the final exam, a student has test scores of 72, 80, 65, 78, and 60. If the final exam counts as one-third of the final grade, what score must the student receive in order to have a final average of 76 percent? Thanks!!

  4. math

    A professor grades students on three tests, four quizzes, and a final examination. Each test counts as two quizzes and the final examination counts as two tests. Sara has test scores of 60, 80, and 89. Sara's quiz scores are 85,

  1. Math

    A class of 12 students has taken an exam, and the mean of their scores is 71. One student takes the exam late, and scores 92. After including the new score, what is the mean score for all 13 exams?

  2. Statistics

    For a 10 point quiz, the professor recorded the following scores for 8 students: 7, 8, 3, 9, 10, 6, 8, 5 What is the Mean for this set of scores?

  3. Statistics

    In your biology class, your final grade is based on several things: a lab score, scores on two major tests, and your score on the final exam. There are 100 points available for each score. However, the lab score is worth 15% of

  4. Math

    Suppose that scores on the Math SAT exam follow a Normal distribution with mean 500 and standard deviation 100. Two students that have taken the exam are selected at random. What is the probability that the sum of their scores

You can view more similar questions or ask a new question.