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Question 1:

What does it mean if a confidence interval includes the value zero?

A) The result is statistically significant
B) The result is not statistically significant
C) There is uncertainty in the estimate
D) The sample size is too small

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Explanation: The correct answer is B) The result is not statistically significant. If a confidence interval includes the value zero, it indicates that the observed effect is not statistically significant. The range of plausible values includes the possibility of no effect, suggesting that the result is not statistically distinguishable from zero.

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Question 2:

What does it mean if the p-value is less than the significance level (e.g., p < 0.05)?

A) The result is statistically significant
B) The result is not statistically significant
C) The result is inconclusive
D) The result is not interpretable

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Explanation: The correct answer is A) The result is statistically significant. If the p-value is less than the significance level (e.g., p < 0.05), it indicates that the observed result is statistically significant. The probability of obtaining the observed result or more extreme results by chance, assuming the null hypothesis is true, is less than the predefined significance level.

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Question 3:

What does it mean if the effect size is large?

A) The result is statistically significant
B) The result is not statistically significant
C) The result has practical or substantive significance
D) The result is biased

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Explanation: The correct answer is C) The result has practical or substantive significance. A large effect size indicates that the observed result has practical or substantive importance. It suggests that the magnitude of the difference or relationship between variables is substantial and not merely a statistical artifact.

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Question 4:

What does it mean if the correlation coefficient is close to -1?

A) The variables are not correlated
B) The variables have a weak negative relationship
C) The variables have a strong positive relationship
D) The variables have a strong negative relationship

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Explanation: The correct answer is D) The variables have a strong negative relationship. When the correlation coefficient is close to -1, it indicates a strong negative linear relationship between the variables. As one variable increases, the other variable tends to decrease proportionally. The closer the correlation coefficient is to -1, the stronger the negative relationship.

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Question 5:

What does it mean if the confidence level is set to 95%?

A) There is a 95% chance of obtaining a significant result
B) The study has a 95% power to detect an effect
C) The confidence interval will include the true population parameter in 95% of samples
D) The study has a 95% chance of being replicated

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Explanation: The correct answer is C) The confidence interval will include the true population parameter in 95% of samples. When the confidence level is set to 95%, it means that if the study is repeated multiple times and confidence intervals are constructed, approximately 95% of those intervals will include the true population parameter. It provides a measure of the precision and reliability of the estimate.