# 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. 👍 0
2. 👎 0
3. 👁 961
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. 👍 0
2. 👎 0
2. what is a correlation coefficient between two variables

1. 👍 0
2. 👎 0

## Similar Questions

1. ### 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

asked by Papi on September 24, 2016
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?

asked by Jake on June 1, 2010
3. ### 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

asked by dianni on March 8, 2019
4. ### 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

1. ### math

A researcher was interested in the emotional effects of music on exam performance. Before their exam, a professor took one group of students into a room in which calming music was played. A different group of students were taken

asked by Rachael on September 21, 2013
2. ### 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

asked by Zac on March 5, 2012
3. ### statistics

Ten members of a fraternity take a statistics course. Here are their scores on the first exam in the course. 61,74,47,60,62,63,65,79,55,85. In all 135 students took the exam. The third quartile for all 135 scores was 69. How many

asked by Victor on December 9, 2013
4. ### 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

asked by Maria on February 19, 2013
1. ### Statistics

Which Professor? Suppose Professor Alpha and Professor Omega each teach Introductory Biology. You need to Decide which professor to take the class from and have just completed your introductory statistics course. Records obtained

asked by Keonn'a on February 19, 2018
2. ### statistics

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Calculate the correlation coefficient r.

asked by milly on September 28, 2011
3. ### statistics

. A professor is interested in knowing the correlation, if any, of students’ scores on the first and second exams given in his class. Test 1 Test 2 92 86 90 87 89 85 82 90 88 79 92 90 100 92 91 84 Is there a significant

asked by John on February 12, 2012
4. ### statistics

Scores from a statistics exam are reported as deviation scores. Which of the following deviation scores indicates a higher position in the class distribution?

asked by michelle on December 6, 2012