Which of the following values could not represent a correlation coefficient?
a. r = 0.99
b. r = 1.09
c. r = -0.73
d. r = -1.0
Answer questions 3 - 9 from the following problem statement.
An instructor wants to show the students that there is a linear correlation between the number of hours they spent watching TV during a certain weekend and their scores on a test taken the following Monday. The number of television viewing hours and the test scores for 12 randomly selected students are shown in Table 1.
What is value of the correlation coefficient, r?
x 0 1 2 3 3 5 5 5 6 7 7 10
y 96 85 82 74 95 68 76 84 58 65 75 50
Using Table 11 in Appendix B of the text, what is the critical value if α = 0.05?
Which of the following is true at α = 0.05?
a. |r| > critical value
b. |r| < critical value
c. |r| = critical value
d. None of the above
What are the null and alternative hypotheses for this given problem?
a. Ho: ρ = 0; Ha: ρ ≠ 0
b. Ho: ρ ≥ 0; Ha: ρ < 0
c. Ho: ρ ≤ 0; Ha: ρ > 0
d. Ho: ρ < 0; Ha: ρ ≥ 0
If a hypothesis test at α = 0.05, has been performed using Table 5 in Appendix B, then what are the rejection regions?
a. t < -2.447 & t > 2.447
b. t < -1.812 & t > 1.812
c. t < -2.228 & t > 2.228
d. t < -0.7 & t > 0.7
What is the value of standardized test statistics, t?
Which pair of conclusions is appropriate for this given problem?
a. The correlation is not significant; reject the null hypothesis.
b. The correlation is significant; reject the null hypothesis.
c. The correlation is not significant; fail to reject the null hypothesis.
d. The correlation is significant; fail to reject the null hypothesis.
If ŷ is the predicted value for a given x-value and b is the y-intercept then the equation of a regression line for an independent variable x and a dependent variable y is
a. ŷ = mx + b, where m = slope.
b. x = ŷ + mb, where m = slope.
c. ŷ = x/m + b, where m = slope.
d. ŷ = x + mb, where m = slope.
Answer questions 11- 14 from the following table.
The ages (in years) of seven children and number of words in their vocabulary is given in Table 2.
What is the value of slope, m of the equation of regression line for the given data?
Age, x 3 4 4 5 6 2 3
Vocabulary size, y 1100 1300 1500 2100 2600 460 1200
a. m = -504.474
b. m = -490.791
c. m = 510.789
d. m = 1300
What is the value of y-intercept, b of the equation of regression line for the given data?
Using the regression line equation for the given data, find the value of y for x = 4.
What is the standard error of estimate, se for this given problem?
Which of the following indicates a strong positive correlation?
a. r = 0
b. r = -0.793
c. r = 0.913
d. r = 0.45
The coefficient of determination is the
a. ratio of the explained variation to the total deviation.
b. ratio of the unexplained deviation to the explained deviation.
c. ratio of the unexplained deviation to the total variation.
d. ratio of the explained variation to the total variation.
If the correlation coefficient r = 0.5 then the coefficient of determination is
Which one of the following statement is false?
a. A nonparametric test is a hypothesis test.
b. A nonparametric test requires a specific condition.
c. Nonparametric tests are easier to perform than corresponding parametric tests.
d. Nonparametric tests are less efficient than parametric tests.
Which of the following statement is true for using Wilcoxon signed-test and
Wilcoxon rank sum test?
a. If the samples are dependent we can use a Wilcoxon signed-rank test.
b. If the samples are independent we can use a Wilcoxon rank sum test.
c. None of the above.
d. Both of A & B.
The condition(s) for using a Kruskal-Wallis test is/are
a. The sample must be randomly selected.
b. The size of each sample must be at least 10.
c. None of above.
d. Both of A & B.
The solutions gives answers to various multiple choice questions from correlation and regression.