Chapter 1. Checking the Conditions for Inference

Correct. Residual equals observed y minus predicted y or y - \( \widehat{y} \).

Incorrect. Residual equals observed y minus predicted y or y - \( \widehat{y} \).

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Correct. A residual plot is a scatterplot of residuals versus observed x values. It is NOT a scatterplot of the observed y values versus the observed x values.

Incorrect. A residual plot is a scatterplot of residuals versus observed x values. It is NOT a scatterplot of the observed y values versus the observed x values.

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Correct. This is a correct statement.

Incorrect. This is a correct statement.

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Correct. A smile or frown pattern in a residual plot indicates non-linearity.

Incorrect. A smile or frown pattern in a residual plot indicates non-linearity.

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Correct. A megaphone pattern in the residual plot indicates unequal variation in the y’s for all x values.

Incorrect. A megaphone pattern in the residual plot indicates unequal variation in the y’s for all x values.

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Correct. As with other t procedures an outlier or strong skewness indicates non-Normality.

Incorrect. As with other t procedures an outlier or strong skewness indicates non-Normality.

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Correct. With n = 92, the sample size is large enough to apply the Central Limit Theorem so Normality is ok.

Incorrect. With n = 92, the sample size is large enough to apply the Central Limit Theorem so Normality is ok.

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Correct. This is a correct statement.

Incorrect. This is a correct statement.

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Correct. Since we don’t see curvature in the scatterplot and we don’t see a smile or frown pattern in the residual plot, these plots do not indicate non-linearity.

Incorrect. Since we don’t see curvature in the scatterplot and we don’t see a smile or frown pattern in the residual plot, these plots do not indicate non-linearity.

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Correct. Since we see curvature in the scatterplot and we see a smile pattern in the residual plot, these plots do indicate non-linearity.

Incorrect. Since we see curvature in the scatterplot and we see a smile pattern in the residual plot, these plots do indicate non-linearity.

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Correct. Since we don’t see a megaphone in the residual plot, these plots do not indicate non-constant standard deviation.

Incorrect. Since we don’t see a megaphone in the residual plot, these plots do not indicate non-constant standard deviation.

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Correct. Since we don’t see curvature in the scatterplot and we don’t see a smile or frown pattern in the residual plot, these plots do not indicate non-linearity.

Incorrect. Since we don’t see curvature in the scatterplot and we don’t see a smile or frown pattern in the residual plot, these plots do not indicate non-linearity.

2

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Correct. Since we don’t see a megaphone in the residual plot, these plots do not indicate non-constant standard deviation.

Incorrect. Since we don’t see a megaphone in the residual plot, these plots do not indicate non-constant standard deviation.

2

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Correct. Since we don’t see curvature in the scatterplot and we don’t see a smile or frown in the residual plot, these plots do not indicate non-linearity.

Incorrect. Since we don’t see curvature in the scatterplot and we don’t see a smile or frown in the residual plot, these plots do not indicate non-linearity.

2

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Correct. Since we see a megaphone pattern in both the scatterplot and the residual plot, these plots indicate non-constant standard deviation.

Incorrect. Since we see a megaphone pattern in both the scatterplot and the residual plot, these plots indicate non-constant standard deviation.

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Correct. With sample size n = 9, the outlier in this histogram of the residuals indicates lack of Normality.

Incorrect. With sample size n = 9, the outlier in this histogram of the residuals indicates lack of Normality.

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