Biostatistics Flashcards

Flashcards covering key concepts in biostatistics based on lecture notes.

What is a key assumption of parametric tests?

The population is normally distributed.

Which test is used to compare the means of two independent groups?

Independent samples t-test.

Which parametric test is appropriate to compare means from more than two groups?

ANOVA.

In a paired t-test, what must be true of the data?

The data must be matched or from the same subject group.

Which of the following is not a parametric test?

Mann-Whitney U test.

What assumption is made by ANOVA regarding variance?

Homogeneity of variance across groups.

When is a Z-test preferred over a t-test?

When population standard deviation is known.

What does a significant result in a parametric test (e.g., p < 0.05) indicate?

There is strong evidence against the null hypothesis.

Which of the following is a condition for using a parametric test regarding independence?

The observations must be independent.

Which of the following is a non-parametric test?

Mann-Whitney U test.

When are non-parametric tests most appropriate?

When data is categorical or ordinal.

What is the Wilcoxon Signed-Rank Test used for?

To compare paired or matched samples.

Which test is the non-parametric equivalent of the independent t-test?

Mann-Whitney U test.

Which non-parametric test is used for testing association between two categorical variables?

Chi-square test of independence.

What is the Kruskal-Wallis test used to compare?

More than two independent groups.

What does Spearman’s rank correlation measure?

Association between two ordinal variables.

What is a key assumption of non-parametric tests regarding data distribution?

No assumption about data distribution.

What is the main disadvantage of non-parametric tests regarding power?

They are generally less powerful than parametric tests.

Which test is used as the non-parametric alternative to one-way ANOVA?

Kruskal-Wallis test.

What is a Type I error in hypothesis testing?

Rejecting a true null hypothesis.

What is a Type II error in hypothesis testing?

Failing to reject a false null hypothesis.

Which scenario increases the risk of a Type II error when regarding the significance level?

Having a very low significance level (α).

What is a good way to reduce the likelihood of a Type II error?

Increase the sample size.

What is the main purpose of a normality test in statistics?

To determine if a dataset is normally distributed.

Which of the following is a commonly used normality test?

Shapiro-Wilk Test.

What does a p-value less than 0.05 in a normality test typically indicate?

The data significantly deviates from normality.

Which of the following normality tests is more suitable for small sample sizes (n < 30)?

Shapiro-Wilk Test.

What is the primary purpose of a t-test?

To compare means between two groups.

Which of the following is the correct scenario for using a one-way ANOVA?

Comparing the means of more than two independent groups.

What assumption is common to both ANOVA and t-tests concerning population distribution?

The samples must come from normally distributed populations.

If an ANOVA test is significant (p < 0.05), what should you do next?

Perform a post-hoc test to identify which means differ.

What does the Pearson correlation coefficient (r) measure?

The strength and direction of a linear relationship between two variables.

What is the range of values that the Pearson correlation coefficient can take?

-1 to 1.

What kind of linear relationship does a Pearson correlation coefficient of r = -0.85 indicate?

A strong negative linear relationship.

In simple linear regression, what does the slope of the regression line represent?

The change in the dependent variable for a one-unit increase in the independent variable.

What is the main purpose of linear regression?

To predict the value of one variable based on another.

What does the null hypothesis (H₀) generally state?

There is no effect or no difference.

Which of the following best represents an alternative hypothesis (H₁)?

The new teaching method improves scores.

In hypothesis testing, what is the purpose of the null hypothesis?

To serve as a statement to be tested and possibly rejected.

What is a correctly stated null hypothesis for testing if a new diet changes average weight?

H₀: The new diet has no effect on average weight.