Posted by Cole Brown on Monday, March 4, 2013 at 1:06am.
1. For the following scores,
X Y
1 6
4 1
1 4
1 3
3 1
Sketch a scatter plot and estimate the value of the
Pearson correlation.
b. Compute the Pearson correlation
2. For the following set of scores,
X Y
6 4
3 1
5 0
6 7
4 2
6 4
a. Compute the Pearson correlation.
b. Add 2 points to each X value and compute the correlation for the modified scores. How does adding a constant to every score affect the value
of the correlation?
c. Multiply each of the original X values by 2 and compute the correlation for the modified scores. How does multiplying each score by a constant
affect the value of the correlation?
3. To simplify the weight variable, the women are classified into five categories that measure actual weight relative to height, from 1 thinnest
to 5 heaviest. Income figures are annual income (in thousands), rounded to the nearest $1,000.
a. Calculate the Pearson correlation for these data.
b. Is the correlation statistically significant? Use a twotailed test with .05.
Weight (X) Income (Y)
1 125
2 78
4 49
3 63
5 35
2 84
5 38
3 51
1 93
4 44
4. Assume a twotailed test with .05.
(Note: The table does not list all the possible df values. Use the sample size corresponding to the appropriate
df value that is listed in the table.)
a. A correlation of r 0.30.
b. A correlation of r 0.25.
c. A correlation of r 0.20.
5. A professor obtains SAT scores and freshman grade point averages (GPAs) for a group of n 15 college students. The SAT scores have a mean of M 580
with SS 22,400, and the GPAs have a mean of 3.10 with SS 1.26, and SP 84.
a. Find the regression equation for predicting GPA from SAT scores.
b. What percentage of the variance in GPAs is accounted for by the regression equation? (Compute the correlation, r, then find r2.)
c. Does the regression equation account for a significant portion of the variance in GPA? use a=.05 to evaluate the Fratio.
6. a. One set of 20 pairs of scores, X and Y values, produces a correlation of r 0.70. If SSY 150, find the standard error of estimate for the regression line.
b. A second set of 20 pairs of X and Y values produces of correlation of r 0.30. If SSY 150, find the standard error of estimate for the regression line.
7. A researcher obtained the following multipleregression equation using two predictor variables:
Yˆ 0.5X1 4.5X2 9.6. Given that SSY 210, the
SP value for X1 and Y is 40, and the SP value for X2 and Y is 9, find R2, the percentage of variance accounted for by the equation.

Stat  Dr. Jane, Monday, March 4, 2013 at 9:12am
Looks like someone's homework assignment or maybe even a take home test. No one here will do your homework. Work out the problems and we will be happy to check your answers.

Stat  jkj, Tuesday, April 30, 2013 at 11:51pm
kkj

Stat  Anonymous, Tuesday, November 17, 2015 at 9:44pm
sa

Stat  Margaret Johnson, Friday, March 18, 2016 at 12:28am
5. A professor obtains SAT scores and freshman grade point averages (GPAs) for a group of n 15 college students. The SAT scores have a mean of M 580
with SS 22,400, and the GPAs have a mean of 3.10 with SS 1.26, and SP 84.
a. Find the regression equation for predicting GPA from SAT scores.
b. What percentage of the variance in GPAs is accounted for by the regression equation? (Compute the correlation, r, then find r2.)
c. Does the regression equation account for a significant portion of the variance in GPA? use a=.05 to evaluate the Fratio
Answer This Question
Related Questions
 Statistics  For the following set of scores: X Y 6 4 3 1 5 0 6 7 4 2 6 4 a) ...
 Psychology Statistics  2 For a sample of n = 20 individuals, how large a ...
 statistics in psychology  11. Make up a scatter diagram with 10 dots for each ...
 Statistics  1.What is the p value (“significance level”)? What does this p ...
 statistics  Given the following scatter diagram , the sample correlation ...
 math  Calculate the Pearson ProductMoment Coefficient of Correlation (r) for ...
 STAT  Calculate SP (the sum of products of deviations) for the following scores...
 Statistics  How is the statistical application of Pearson r used for ...
 statistics  For problems 12 to 14, do the following: (a) Make a scatter diagram...
 statistics  For problems 12 to 14, do the following: (a) Make a scatter diagram...
More Related Questions