biostatistics

Which of the following is the most appropriate measure of central tendency for skewed data?

• • Mean

• • Range

• • Median

• • Mode

2. In a normal distribution, what percentage of values falls within one standard deviation of the mean?

• • 50%

• • 99.7%

• • 95%

• • 68%

• . The probability of rejecting a true null hypothesis is called:

• • Confidence interval

• • Type II error

• • Type I error

• • Significance level

Which of the following is not a measure of dispersion?

• • Mean

• • Variance

• • Standard deviation

• • Range

In a dental study, which statistical test is most appropriate to compare the mean decayed, missing, and filled teeth (DMFT) scores between two independent groups?

• • ANOVA

• • t-test

• • Correlation analysis

• • Chi-square test

What does a p-value less than 0.05 indicate in hypothesis testing?

• • There is weak evidence against the null hypothesis

• • The alternative hypothesis is rejected

• • There is strong evidence against the null hypothesis

• • The null hypothesis is accepted

Which test would be most appropriate to examine the association between two categorical variables in a study?

• • Chi-square test

• • ANOVA

• • t-test

• • Correlation analysis

A study in public health dentistry finds a correlation coefficient of -0.85 between sugar consumption and oral health. What does this indicate?

• • Weak negative correlation

• • Strong negative correlation

• • Strong positive correlation

• • Weak positive correlation

Which measure is used to quantify the amount of variation or dispersion in a set of values?

• • Mode

• • Mean

• • Standard deviation

• • Median

Which of the following is NOT an assumption of the t-test?

• • The population variances are equal

• • The data must be ordinal

• • The samples are independent

• • The data are normally distributed