A Practical Approach to Using Statistics in Health Research – From Planning to Reporting
From Planning to Reporting
Samenvatting
A hands–on guide to using statistics in health research, from planning, through analysis, and on to reporting
A Practical Approach to Using Statistics in Health Research offers an easy to use, step–by–step guide for using statistics in health research. The authors use their experience of statistics and health research to explain how statistics fit in to all stages of the research process. They explain how to determine necessary sample sizes, interpret whether there are statistically significant difference in outcomes between groups, and use measured effect sizes to decide whether any changes are large enough to be relevant to professional practice.
The text walks you through how to identify the main outcome measure for your study and the factor which you think may influence that outcome and then determine what type of data will be used to record both of these. It then describes how this information is used to select the most appropriate methods to report and analyze your data. A step–by–step guide on how to use a range of common statistical procedures are then presented in separate chapters. To help you make sure that you are using statistics robustly, the authors also explore topics such as multiple testing and how to check whether measured data follows a normal distribution. Videos showing how to use computer packages to carry out all the various methods mentioned in the book are available on our companion web site. This book:
Covers statistical aspects of all the stages of health research from planning to final reporting
Explains how to report statistical planning, how analyses were performed, and the results and conclusion
Puts the spotlight on consideration of clinical significance and not just statistical significance
Explains the importance of reporting 95% confidence intervals for effect size
Includes a systematic guide for selection of statistical tests and uses example data sets and videos to help you understand exactly how to use statistics
Written as an introductory guide to statistics for healthcare professionals, students and lecturers in the fields of pharmacy, nursing, medicine, dentistry, physiotherapy, and occupational therapy, A Practical Approach to Using Statistics in Health Research:From Planning to Reporting is a handy reference that focuses on the application of statistical methods within the health research context.
Specificaties
Inhoudsopgave
<p>1 Introduction 1</p>
<p>1.1 At Whom is This Book Aimed? 1</p>
<p>1.2 At What Scale of Project is This Book Aimed? 2</p>
<p>1.3 Why Might This Book be Useful for You? 2</p>
<p>1.4 How to Use This Book 3</p>
<p>1.5 Computer Based Statistics Packages 4</p>
<p>1.6 Relevant Videos etc. 5</p>
<p>2 Data Types 7</p>
<p>2.1 What Types of Data are There and Why Does it Matter? 7</p>
<p>2.2 Continuous Measured Data 7</p>
<p>2.3 Ordinal Data 13</p>
<p>2.4 Categorical Data 14</p>
<p>2.5 Ambiguous Cases 14</p>
<p>2.6 Relevant Videos etc. 15</p>
<p>3 Presenting and Summarizing Data 17</p>
<p>3.1 Continuous Measured Data 17</p>
<p>3.2 Ordinal Data 21</p>
<p>3.3 Categorical Data 23</p>
<p>3.4 Relevant Videos etc. 24</p>
<p>Appendix 1: An Example of the Insensitivity of the Median When Used to Describe Data from an Ordinal Scale With a Narrow Range of Possible Values 25</p>
<p>4 Choosing a Statistical Test 27</p>
<p>4.1 Identify the Factor and Outcome 27</p>
<p>4.2 Identify the Type of Data Used to Record the Relevant Factor 29</p>
<p>4.3 Statistical Methods Where the Factor is Categorical 30</p>
<p>4.4 Correlation and Regression with a Measured Factor 34</p>
<p>4.5 Relevant Additional Material 38</p>
<p>5 Multiple Testing 39</p>
<p>5.1 What Is Multiple Testing and Why Does It Matter? 39</p>
<p>5.2 What Can We Do to Avoid an Excessive Risk of False Positives? 40</p>
<p>6 Common Issues and Pitfalls 43</p>
<p>6.1 Determining Equality of Standard Deviations 43</p>
<p>6.2 How Do I Know, in Advance, How Large My SD Will Be? 43</p>
<p>6.3 One ]Sided Versus Two ]Sided Testing 44</p>
<p>6.4 Pitfalls That Make Data Look More Meaningful Than It Really Is 45</p>
<p>6.5 Discussion of Statistically Significant Results 47</p>
<p>6.6 Discussion of Non ]Significant Results 50</p>
<p>6.7 Describing Effect Sizes with Non ]Parametric Tests 51</p>
<p>6.8 Confusing Association with a Cause and Effect Relationship 52</p>
<p>7 Contingency Chi ]Square Test 55</p>
<p>7.1 When Is the Test Appropriate? 55</p>
<p>7.2 An Example 55</p>
<p>7.3 Presenting the Data 57</p>
<p>7.4 Data Requirements 59</p>
<p>7.5 An Outline of the Test 59</p>
<p>7.6 Planning Sample Sizes 59</p>
<p>7.7 Carrying Out the Test 60</p>
<p>7.8 Special Issues 61</p>
<p>7.9 Describing the Effect Size 61</p>
<p>7.10 How to Report the Analysis 65</p>
<p>7.11 Confounding and Logistic Regression 67</p>
<p>7.12 Larger Tables 69</p>
<p>8 Independent Samples (Two ]Sample) T ]Test 73</p>
<p>8.1 When Is the Test Applied? 73</p>
<p>8.2 An Example 73</p>
<p>8.3 Presenting the Data 75</p>
<p>8.4 Data Requirements 75</p>
<p>8.5 An Outline of the Test 78</p>
<p>8.6 Planning Sample Sizes 79</p>
<p>8.7 Carrying Out the Test 79</p>
<p>8.8 Describing the Effect Size 79</p>
<p>8.9 How to Describe the Test, the Statistical and Practical Significance of Your Findings in Your Report 80</p>
<p>8.10 Relevant Videos etc. 81</p>
<p>9 Mann Whitney Test 83</p>
<p>9.1 When Is the Test Applied? 83</p>
<p>9.2 An Example 83</p>
<p>9.3 Presenting the Data 85</p>
<p>9.4 Data Requirements 86</p>
<p>9.5 An Outline of the Test 87</p>
<p>9.6 Statistical Significance 87</p>
<p>9.7 Planning Sample Sizes 87</p>
<p>9.8 Carrying Out the Test 88</p>
<p>9.9 Describing the Effect Size 88</p>
<p>9.10 How to Report the Test 89</p>
<p>9.11 Relevant Videos etc. 91</p>
<p>10 One ]Way Analysis of Variance (ANOVA) Including Dunnett s and Tukey s Follow Up Tests 93</p>
<p>10.1 When Is the Test Applied? 93</p>
<p>10.2 An Example 93</p>
<p>10.3 Presenting the Data 94</p>
<p>10.4 Data Requirements 94</p>
<p>10.5 An Outline of the Test 98</p>
<p>10.6 Follow Up Tests 98</p>
<p>10.7 Planning Sample Sizes 99</p>
<p>10.8 Carrying Out the Test 100</p>
<p>10.9 Describing the Effect Size 101</p>
<p>10.10 How to Report the Test 101</p>
<p>10.11 Relevant Videos etc. 103</p>
<p>11 Kruskal Wallis 105</p>
<p>11.1 When Is the Test Applied? 105</p>
<p>11.2 An Example 105</p>
<p>11.3 Presenting the Data 106</p>
<p>11.4 Data Requirements 109</p>
<p>11.5 An Outline of the Test 110</p>
<p>11.6 Planning Sample Sizes 110</p>
<p>11.7 Carrying Out the Test 110</p>
<p>11.8 Describing the Effect Size 111</p>
<p>11.9 Determining Which Group Differs from Which Other 111</p>
<p>11.10 How to Report the Test 111</p>
<p>11.11 Relevant Videos etc. 114</p>
<p>12 McNemar s Test 115</p>
<p>12.1 When Is the Test Applied? 115</p>
<p>12.2 An Example 115</p>
<p>12.3 Presenting the Data 116</p>
<p>12.4 Data Requirements 116</p>
<p>12.5 An Outline of the Test 118</p>
<p>12.6 Planning Sample Sizes 118</p>
<p>12.7 Carrying Out the Test 119</p>
<p>12.8 Describing the Effect Size 119</p>
<p>12.9 How to Report the Test 119</p>
<p>12.10 Relevant Videos etc. 121</p>
<p>13 Paired T ]Test 123</p>
<p>13.1 When Is the Test Applied? 123</p>
<p>13.2 An Example 125</p>
<p>13.3 Presenting the Data 125</p>
<p>13.4 Data Requirements 126</p>
<p>13.5 An Outline of the Test 128</p>
<p>13.6 Planning Sample Sizes 129</p>
<p>13.7 Carrying Out the Test 129</p>
<p>13.8 Describing the Effect Size 129</p>
<p>13.9 How to Report the Test 130</p>
<p>13.10 Relevant Videos etc. 131</p>
<p>14 Wilcoxon Signed Rank Test 133</p>
<p>14.1 When Is the Test Applied? 133</p>
<p>14.2 An Example 134</p>
<p>14.3 Presenting the Data 134</p>
<p>14.4 Data Requirements 136</p>
<p>14.5 An Outline of the Test 137</p>
<p>14.6 Planning Sample Sizes 138</p>
<p>14.7 Carrying Out the Test 139</p>
<p>14.8 Describing the Effect Size 139</p>
<p>14.9 How to Report the Test 140</p>
<p>14.10 Relevant Videos etc. 141</p>
<p>15 Repeated Measures Analysis of Variance 143</p>
<p>15.1 When Is the Test Applied? 143</p>
<p>15.2 An Example 144</p>
<p>15.3 Presenting the Data 144</p>
<p>15.4 Data Requirements 146</p>
<p>15.5 An Outline of the Test 148</p>
<p>15.6 Planning Sample Sizes 149</p>
<p>15.7 Carrying Out the Test 150</p>
<p>15.8 Describing the Effect Size 150</p>
<p>15.9 How to Report the Test 151</p>
<p>15.10 Relevant Videos etc. 153</p>
<p>16 Friedman Test 155</p>
<p>16.1 When Is the Test Applied? 155</p>
<p>16.2 An Example 157</p>
<p>16.3 Presenting the Data 157</p>
<p>16.4 Data Requirements 160</p>
<p>16.5 An Outline of the Test 160</p>
<p>16.6 Planning Sample Sizes 161</p>
<p>16.7 Follow Up Tests 161</p>
<p>16.8 Carrying Out the Tests 162</p>
<p>16.9 Describing the Effect Size 162</p>
<p>16.10 How to Report the Test 162</p>
<p>16.11 Relevant Videos etc. 164</p>
<p>17 Pearson Correlation 165</p>
<p>17.1 Presenting the Data 165</p>
<p>17.2 Correlation Coefficient and Statistical Significance 166</p>
<p>17.3 Planning Sample Sizes 167</p>
<p>17.4 Effect Size and Practical Relevance 167</p>
<p>17.5 Regression 169</p>
<p>17.6 How to Report the Analysis 170</p>
<p>17.7 Relevant Videos etc. 171</p>
<p>18 Spearman Correlation 173</p>
<p>18.1 Presenting the Data 173</p>
<p>18.2 Testing for Evidence of Inappropriate Distributions 174</p>
<p>18.3 Rho and Statistical Significance 174</p>
<p>18.4 An Outline of the Significance Test 175</p>
<p>18.5 Planning Sample Sizes 175</p>
<p>18.6 Effect Size 176</p>
<p>18.7 Where Both Measures Are Ordinal 176</p>
<p>18.8 How to Report Spearman Correlation Analyses 178</p>
<p>18.9 Relevant Videos etc. 180</p>
<p>19 Logistic Regression 181</p>
<p>19.1 Use of Logistic Regression with Categorical Outcomes 181</p>
<p>19.2 An Outline of the Significance Test 182</p>
<p>19.3 Planning Sample Sizes 182</p>
<p>19.4 Results of the Analysis 184</p>
<p>19.5 Describing the Effect Size 184</p>
<p>19.6 How to Report the Analysis 185</p>
<p>19.7 Relevant Videos etc. 187</p>
<p>20 Cronbach s Alpha 189</p>
<p>20.1 Appropriate Situations for the Use of Cronbach s Alpha 189</p>
<p>20.2 Inappropriate Uses of Alpha 190</p>
<p>20.3 Interpretation 190</p>
<p>20.4 Reverse Scoring 191</p>
<p>20.5 An Example 191</p>
<p>20.6 Performing and Interpreting the Analysis 192</p>
<p>20.7 How to Report Cronbach s Alpha Analyses 193</p>
<p>20.7 Relevant Videos etc. 195</p>
<p>Glossary 197</p>
<p>Videos 209</p>
<p>Index 211</p>