Slopes
To construct a confidence interval, we add and subtract a multiple of the SEM from the:
Population mean
Sample mean
Standard deviation of the sample
Residuals
What does the Central Limit Theorem state in the context of constructing confidence intervals?
The sample size should be at least 30 for normal distribution
The sample regression line accurately represents the population regression line
The standard deviation of the residuals should be known
The population standard deviation should be small
What type of sampling involves selecting every kth individual from a list or queue?
Simple random sampling
Convenience sampling
Stratified random sampling
Systematic sampling
How does a confidence interval for a population slope support or refute claims about causality in an observational study?
It proves that changes in one variable will cause changes in another since they are statistically related.
It shows that any value within its range will have no effect on determining causality within data trends.
It only quantifies how well future samples could estimate this slope, but cannot establish cause-and-effect relationships.
It reflects all possible values of correlation coefficients establishing a direct causal connection.
Which of the following factors affects the width of a confidence interval?
Mean of the sample
Standard deviation of the population
Sample size, level of confidence, and degree of variation in the sample
Margin of error and point estimate
If a confidence interval for the slope of a regression model does not include zero, what can we conclude about the relationship between the explanatory and response variables?
There is evidence of a statistically significant linear relationship.
There is no evidence of any relationship between the variables.
The slope of the regression line must be positive.
The variability in y cannot be explained by x at all.
To construct a confidence interval for the slope in simple linear regression, which assumption about residuals must be met?
Residuals are normally distributed.
Residuals have constant variance across all levels of x.
Residuals equal zero for all observations.
Each residual is larger than the previous residual.

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If a linear regression model has a slope confidence interval of (3.5, 4.7) from one dataset and (3.6, 4.8) from another under the same conditions, what can be inferred about the robustness of the model?
The difference in intervals suggests a lack of consistency in variance between datasets.
The model lacks robustness since the intervals do not exactly match.
Inference on robustness cannot be made without knowing the confidence level.
The model is likely robust as the intervals are similar across datasets.
Which statement correctly explains why extrapolation from a regression model can be misleading without implying causation?
Predictions made outside the observed data range assume existing linear relations continue unchanged, potentially overlooking other influences.
Extrapolations always produce accurate forecasts because high R-squared values validate extended linearity regardless of where.
Predictions confirm underlying causes since mathematical models represent reality fully ensuring accuracy even far from known points.
Since r-values measure strength direction trend, therefore stretching them beyond provided information maintains their integrity completely unaffected by distance.
What does the standard deviation of the residuals represent?
Standard error of the estimate
Variability of the sample mean
Dispersion of the sample values around the population mean
Dispersion of the residuals around the mean