Biostatistics

Topics in this chapter

• Descriptive Statistics and Data Display
• Normal Distribution and Empirical Rule
• Sampling and Standard Error
• Hypothesis Testing and Errors
• Chi-Square Tests for Categorical Data
• ANOVA for Group Comparisons
• Correlation Analysis
• Screening Test Accuracy

Practice questions

1. Question 1Q-97856C

   A clinical trial is conducted to compare a new antihypertensive drug with a standard drug. The mean reduction in systolic blood pressure is 15 mmHg in the new drug group and 12 mmHg in the standard group, with a calculated p-value of 0.03. Assuming the significance level (alpha) was set at 0.05, what is the correct statistical conclusion?

   1. A.Accept the null hypothesis because the difference in means is small.
   2. B.Reject the null hypothesis and conclude there is a statistically significant difference.
   3. C.Reject the alternative hypothesis because the p-value is less than 0.05.
   4. D.Accept the alternative hypothesis with a 97% confidence level.
   See the answer and solution
2. Question 2Q-840C7B

   In a skewed distribution of family incomes in a metropolitan city, which of the following measures of central tendency is least affected by extreme outlier values (extremely high incomes)?

   1. A.Arithmetic mean
   2. B.Median
   3. C.Geometric mean
   4. D.Sum of values
   See the answer and solution
3. Question 3Q-A1694A

   A researcher wishes to study the association between smoking status (smoker vs. non-smoker) and the incidence of lung cancer (yes vs. no) in a population. Which statistical test is most appropriate for analyzing this data?

   1. A.Paired t-test
   2. B.Chi-square test of independence
   3. C.Pearson correlation coefficient
   4. D.Repeated measures ANOVA
   See the answer and solution
4. Question 4Q-8AE43E

   During a screening program for diabetes, a new rapid test is evaluated against the gold standard oral glucose tolerance test. If the cutoff value of the rapid test is increased to reduce false positives, what will be the inevitable effect on its sensitivity and specificity?

   1. A.Sensitivity increases, specificity decreases
   2. B.Sensitivity decreases, specificity increases
   3. C.Both sensitivity and specificity increase
   4. D.Both sensitivity and specificity decrease
   See the answer and solution
5. Question 5Q-D42536

   A study reports that the correlation coefficient (r) between maternal age and birth weight is -0.15 with a p-value of 0.40. How should this result be interpreted?

   1. A.There is a strong inverse linear relationship that is statistically significant.
   2. B.There is a weak inverse linear relationship that is statistically significant.
   3. C.There is a weak linear relationship, but it is not statistically significant.
   4. D.There is no relationship at all because r is negative.
   See the answer and solution