ALLIED MAT130 MODULE 6 check your understanding

Question Points

1. Given the linear correlation coefficient r and the sample size n, determine the critical values of r and use your finding to state whether or not the given r represents a significant linear correlation. Use a significance level of 0.05. r = 0.434, n = 15

a. Critical values: r = ±0.514, significant linear correlation

b. Critical values: r = ±0.532, no significant linear correlation

c. Critical values: r = ±0.514, significant linear correlation

d. Critical values: r = ±0.514, no significant linear correlation

2. Complete the following definition: Discordant pairs of results come from:

a. matched pairs of results in which the two categories are the same.

b. unmatched pairs of results in which the two categories are the same.

c. matched pairs of results in which the two categories are different.

d. unmatched pairs of results in which the two categories are different.

3. Determine what completes the following definition: A _____ exists between two variables when the values of one variable are somehow associated with the values of the other variable.

a. correlation

b. coefficient

c. regression

d. residual

4. Is the data point, P, an outlier, an influential point, both, or neither? The regression equation for a set of paired data is = 1.18 + 1.90x. The values of x run from 3 to 20. A new data point, P(30, 60), is added to the set.

a. Influential point

b. Outlier

c. Both

d. Neither

5.

Find the standard error of estimate for the given paired data. The equation of the regression line for the paired data below is = 6.18286 + 4.33937x. Find the standard error of estimate.

a. 3.1270

b. 2.6959

c. 0.8275

d. 1.6419

6. Complete the following definition: _____ is used for testing the null hypothesis that the frequencies from the discordant categories occur in the same proportion.

a. Fisher Exact test

b. McNemar's test

c. Goodness-of-Fit test

d. Wilcoxon Signed Ranks test

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7. Determine what completes the following definition: The _____ is a measure of the differences between the observed sample y-values and the predicted values that are obtained using the regression equation.

a. Standard error of estimate

b. Prediction interval

c. Multiple regression equation

d. Coefficient of determination

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8.

Construct the indicated prediction interval for an individual y. The equation of the regression line for the paired data below is = 3x and the standard error of estimate is se = 2.2361. Find the 90% prediction interval of y for x = 3.

a. 7.1 < y < 10.9

b. 4.5 < y < 13.5

c. 1.2 < y < 16.8

d. 6.8 < y < 11.2

9.

Use the given data to find the equation of the regression line. Round the final values to three significant digits, if necessary.

a. = 4.98 + 0.425x

b. = 4.88 + 0.525x

c. = 4.88 + 0.625x

d. = 4.98 + 0.725x

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10.

Below are the productivity, dexterity, and job satisfaction ratings of ten randomly selected employees. Find the multiple regression equation that expresses the job satisfaction scores in terms of the productivity and dexterity scores.

a. = 28.28 + 0.237P + 0.728D

b. = 28.28 + 0.517P + 0.0860D

c. = 28.28 + 0.0860P + 0.517D

d. = 28.28 + 0.011P + 0.437D

11.

Use computer software to obtain the multiple regression equation and identify R2, adjusted R2, and the P-value. An anti-smoking group used data in the table to relate the carbon monoxide of various brands of cigarettes to their tar and nicotine content.

a. 0.931, 0.902, 0.000

b. 0.943, 0.034, 0.000

c. 0.861, 0.900, 0.015

d. 0.976, 0.921, 0.002

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12. Which of the following is not a property of the linear correlation coefficient r?

a. The value of r is always between 1 and 1 inclusive.

b. r measures the strength of a non-linear relationship.

c. If all values of either variable are converted to a different scale, the value of r does not change.

d. The value of r is not affected by the choice of x or y.

e. r is very sensitive to outliers in the sense that a single outlier can dramatically affect its value.

13. Complete the following statement regarding relationships among the x2 test statistic, P-values and Goodness-of-Fit. Small x2 values correspond to _____ P-values, which leads to _____ the null hypothesis.

a. Small, failing to reject

b. Large, failing to reject

c. Small, rejecting

d. Large, rejecting

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14. Determine what completes the following definition: A _____ is a table in which frequencies correspond to two variables.

a. Goodness-of-fit table

b. Contingency table

c. Regression table

d. Residual table

15. What is the error, if any, in the stated conclusion? Given: The linear correlation coefficient for the IQ test scores and head circumferences of test subjects is very close to 0. Conclusion: IQ scores and head circumferences are not related in any way.

a. Assuming that correlation implies causality.

b. Basing a conclusion on averages.

c. Assuming there is a linear correlation when there might be some other correlation that is not linear.

d. There is no error.