1. Lecture11 review for final examination
Department of Epidemiology and Biostatistics

2. Final assessment
60% big class quizzes(3) and final writing examination
40% from computer lab

3. Examination 1. Single Choice 20’ 2. terms 3.simple question
4.Complicated question

4. Simple choice (A) The range is a measure of central tendency.
1. Which of the following statements is correct?
(A) The range is a measure of central tendency.
(B) The median is a measure of dispersion.
(C) For a symmetric distribution, the mean is equal to the median.
(D) For a skewed distribution, the variance is a negative number.
2. There are 100 men., with mean cm and standard deviation 4.95cm.in heights ,with mean 61.54kg and standard deviation 4.72kg in weights. Which of the following statements is true?
(A) The variation of the weight is higher than that of the height.
(B) The variation of the height is higher than that of the weight.
(C) The variation of the height is same as the weight.
(D) The variation of the height and that of the weight are not comparable because of different units.
3. A study is conducted among the students in a statistics class, and several variables are recorded, please judges which of following variables are categorical or quantitative.
(A) The blood types of the students are quantitative.
(B) The credit hours available during that semester are quantitative.
(C) The time that students spend waiting in line at the bookstore to pay for his/her textbooks is categorical.
(D) The hometown of the student is quantitative.

5. Summary of Terms Population sample Sample size Parameter Probability
Statistic CI RI
Sampling error
Median CV SD SE
Significance level
Ratio
Proportion
Randomization
Rank sum
Correlation coefficient
Regression coefficient

6. Simple question Question1
What are the sample mean (to 2 decimal places) and median of the following data?
15, 21, 24,16,13,18
Question2 What is difference between SD and SE?

7. Simple question
Question 3 What is difference between CI and RI?

8. Simple question Question 5
Please give 2 examples of qualitative binary categorical data, and ordinal data variables respectively.
Quantitative:
binary data:
Ordinal data:

9. Simple question
The means and SDs of height and weight are followed. How to compare the variation of height and weight of a group of boys of age 12.
weight: mean=40Kg  variance=16kg 
height: mean=140cm  variance=28cm 
Solution:
CV1=16/40=0.4
CV2=28/140=0.2
So weight has more dispersion than height

10. Simple questions
Quiz1
Quiz2

11. More simple question How to control the sampling error?
Solution: 1.to increase sample size
2.to decrease variation,
What are the differences among cardinal data, ordinal data? (explain with examples)
What is the difference between a parametric test and a nonparametric test?

12. Complicated question Quiz3-4 Quiz5 t-test for 2 independent groups.
A study was carried out to investigate the effectiveness of a treatment.50 subjects participated in the study, with 25 being randomly assigned to the “treatment group” and the other 25 to the “control (or placebo) group”. Some results are listed as follows. Please answer these questions

13. Complicated question a. what are the hypotheses for this question?
b. If the t value of significance test is 7.139, how much df and p value? (the critical value is t0.05/2,40= or t0.05/2,50=2.009)
c. What is statistical conclusion?
d. what is medical conclusion?

14. Complicated question
Chi-square test
Rank sum test

15. Thank you for your attention!