1. Practice 1 Tao Yuchun http://cc.jlu.edu.cn/ms.html Medical Statistics
Practical Lesson

2. Review I. Basic concepts 1. Population and Sample
Randomization
2. Probability and Frequency
3. Parameter and Statistic

3. 1. Numerical Variable (Measurement Data)
II. Types of data
1. Numerical Variable (Measurement Data)
quantitatively
2. Categorical Variable (Enumeration Data)
qualitatively
Nominal Variable
Count Data
3. Ordinal variable ( Rank data )

4. III. The Basic Steps of Statistical Work
1. Design of study
2. Collection of data
3. Data Sorting
4. Data Analysis
Descriptive statistics
Inferential statistics

5. (1) Steps of establishing a frequency table
IV. Statistical Description for Measurement
Data
1.1 Frequency Distribution
(1) Steps of establishing a frequency table
(2) Frequency plot ---histogram
(3) The use of frequency table
central tendency
measure of dispersion

6. μ 1.2 Measures for Average ★ (1) Arithmetic Mean (mean)
Suitable to symmetric distribution.

7. Suitable to positive skew distribution, like geometric progression.
(2) Geometric Mean (G)
lg-1 =10x
Suitable to positive skew distribution,
like geometric progression.

8. a. For raw data b. For frequency table (3) Median (M)
Ranking the data, finding the middle value.
For odd number, it is; for even number, it is
mean of two middle values.
b. For frequency table
Suitable to all kinds of data, but usually to
positive skew distribution.

9. 1.3 Measures for variability ★
Add: Percentile --- Px
Symmetric
Positive skew
1.3 Measures for variability ★
(1) Range (R)
R = Maximum - Minimum
Suitable to all kinds of data, but no useful.

10. (2) InterQuartile Range (IQR)
Suitable to all kinds of data, but usually skew
distribution.
(3) Variance and Standard Deviation (S2 and S)

11. Suitable to symmetric distribution.
(4) Coefficient of Variation (CV)
Comparison of the variation of two variables
with different dimensions or bigger difference
of means .

12. Calculative tools I. Scientific calculator
The scientific calculator with statistical
function. (like CASIO fx-3600PV or CASIO fx-82TL)
Calculative method is often:
Input all raw data, press the special
button under statistical mode, you will
get the result (like , S) directly.

13. Many statistical function. The macro of statistical analysis tool.
II. Excel ★
Many statistical function.
The macro of statistical analysis tool.
Using any expression directly.
Many statistical graphs.
See the example
(stat1(English).xls)

14. III. Statistical software
Professional statistical analysis tool.
The special data management and
statistical analysis procedure.
The special executive commands.
Include almost all statistical methods.
SAS, SPSS, Stata, BDMP, …
If you want use it, you should have to
learn another lesson.

15. Practice in class Exercise 1: the blood-glucose(mmol/L) values from
12 randomly selected patients.
5.31, 6.12, 6.53, 6.53, 6.65, 6.66, 6.71, 6.93, 7.05,
7.15, 7.21, 7.35
Please calculate the arithmetic mean, geometric
mean and median; range, quartile range and standard
deviation.

16. Exercise 2: the frequency table of latent period (day)
from 110 certain infectious disease patients.

17. Answer See the Excel file (practice1key.xls)
1) Please calculate the arithmetic mean, geometric mean and
median, which one better reflects the average level ?
2) Please calculate the range, quartile range and standard
deviation, which one better reflects the variation ?
Answer
See the Excel file
(practice1key.xls)

18. Homework There are raw data of temperature（℃）for 102 female
students from certain college(see below).

19. C 1) Please work out a frequency table and a histogram.
Medical Statistics
1) Please work out a frequency table and a histogram.
2) Please calculate the arithmetic mean, median, quartile
range, standard deviation and coefficient of variation. ( C
Practical Lesson

20. CASIO

21. CASIO fx-82TL