Medical Statistics (eBook)

Dr Ramakrishna H K completed MBBS from Government Medical College, Bellary in 1989 and MS in General Surgery at Karnataka Medical College, Hubli 1992 and DNB (Diplomate of National Board) in General Surgery,1993. He started first Upper GI Endoscopy center in 1995 & first laparoscopic surgery center in 2001 in Bhadravathi, a rural area. He started mobile laparoscopic surgery unit started in 2005 to extend the benefits of laparoscopic surgery to nearby rural places. The unit covered a distance of about 60 km radius. He has to his credit several articles published in various journals. He is also a reviewer for many journals like BMJ case reports, World Journal of Gastroenterology.He got many best paper awards in the conferences. He has given many guest lectures in conferences both at state and at national levels. He has convened many symposia in state conferences. He has been judge for award papers in conferences. He is in charge of web site of KSCASI. (www.kscasi.com). He is keenly interested in Medical Statistics.

Foreword 6
Opinion 7
Contents 8
About the Author 11
1: Introduction 12
2: My Journey from a Rural Surgeon to an Author 14
3: Understanding Biostatistics, Probability, and Tests of Significance 20
Skewed Distribution Curve 28
4: Understanding Basic Statistical Terms 31
Measures of Central Tendency 32
Measures of Dispersion or Spread 36
Variance and Standard Deviation 37
Confidence Interval and Confidence Level 41
Errors Type 1 and Type 2 (Alpha and Beta, Respectively) 41
Factors Increasing Type II Error (False Negativity) 42
Conditional Probability 42
Independence 42
Normal or Gaussian Distribution and Skewed Distribution 43
5: Tests of Significance 45
Chi-Square Test or Simply Chi Test 46
Fisher’s Exact Test 50
Formula for Fisher’s Test 50
! Is the Symbol for Factorial 50
Student’s T Test or Gosset’s Test 55
One- and Two-Tailed Tests 58
Paired T Tests 59
ANOVA 61
Which Test to Use? 61
Mann–Whitney–Wilcoxon (MWW) Test 64
Summary 66
6: Other Commonly Used Concepts 77
ANalysis Of VAriance (ANOVA) 77
Rank Test: Wilcoxon Signed-Rank Test 79
Risk and Risk Ratio 80
Odds 81
Odds Ratio 81
Relative Risk Reduction (RRR), Absolute Risk Reduction (ARR), and Number Needed to Treat (NNT) 81
Correlation: Relation Between Two Factors 81
Positive Correlation 82
Negative Correlation 82
Correlation Coefficient (r) 83
Regression 83
Linear Regression 84
Other Types of Regressions 86
Logistic Regression 86
Multiple Regression: To Predict an Outcome 86
The Poisson Regression (Distribution) 87
Cox Regression 87
Survival Analysis 88
Kaplan–Meier Estimator or Survival Graph 89
Multivariate Analysis 89
Power of a Study 90
7: Designing a Study/Clinical Trial/Dissertation, Etc. 94
General Considerations 94
Concerns While Designing a Trial 96
Negative Results 97
Teamwork 98
Phases of Trials: Applies to New Drugs 98
Some Commonly Used Terms 98
Parallel Studies and Crossover Study 99
Planning and Pilot Study 99
Sample Size 101
Pilot Study 102
Collection and Compilation of Data 103
Data 107
Types of Study 107
Data Collection 108
Bias 108
Sampling 110
Sampling Errors and Nonsampling Errors 111
Data Analysis and Inference 112
Presentation of Data and Results 114
Tables 114
Bar Chart 116
Pie Chart 122
Line Chart 123
Area Chart 124
Doughnut Chart 125
Histogram 126
Difference Between Histogram and Bar Chart 129
Clinical Audit 129
Clinical Audit Versus Research 129
Clinical Audit Is an Ongoing Process 130
Problems with Audit 131
Methodology 131
8: Writing an Article for Journals 137
Clear Message 138
Type of the Articles 139
Quality Indicators of a Journal 140
Indexing 140
Impact Factor 140
Uniform Requirement for Manuscript Submission 141
What Happens After Submission? 150
Common Reasons for Rejection of Article or Article Sent Back for Changes (Problems in the Article) 151
Best Chance of Acceptance 151
Plagiarism 152
Peer Review 153
Copyright 154
Literature Review 154
Scholarly Databases 157
Limitations and Issues 159
Open-Access Journals 160
Publish or Perish? 160
9: Evidence-Based Medicine 169
What Is EBM? 169
Why Do We Need EBM? 169
How? 170
The Five-Step Approach to EBM 173
Benefits of EBM 173
Limitations of EBM 174
10: Model Example 175
Postoperative Management Protocol to Be Followed 176
Results 178
Paper 179
Index 186