A clinical pharmacologist is reviewing the baseline characteristics and primary endpoints for a phase 3 multicenter trial of a novel monoclonal antibody targeting IL-6 in patients with seropositive rheumatoid arthritis. To construct the final statistical analysis plan, each outcome variable must be appropriately classified to determine the correct descriptive statistics and graphical representations. Match the clinical trial variables on the left with their most accurate statistical classifications and corresponding descriptive summaries on the right.
- Serum C-reactive protein (CRP) levels (mg/L), which feature a dense clustering of values near the lower limit of quantification alongside a long tail of extremely high measurements in non-responders.Continuous data with a right-skewed distribution; optimally summarized using the median and interquartile range.
- Achievement of the American College of Rheumatology 20% improvement criteria (ACR20) at week 24, recorded solely as 'Achieved' or 'Not Achieved'.Dichotomous nominal data; appropriately analyzed using relative frequencies and typically visualized with a bar chart or pie chart.
- Patient Global Assessment of Disease Activity, categorized strictly as 'Remission', 'Low', 'Moderate', or 'High'.Ordinal categorical data; categories possess an inherent rank sequence but lack a standardized mathematical interval between them.
- Baseline hemoglobin levels (g/dL), which demonstrate a symmetric, bell-shaped clustering around a central expected value with equal distribution on both sides.Normally distributed continuous data; optimally summarized using the mean, with approximately 95% of values falling within two standard deviations.
Cevap
CRP matches with right-skewed continuous data; ACR20 matches with dichotomous nominal data; Disease Activity Assessment matches with ordinal categorical data; and Hemoglobin matches with normally distributed continuous data.
CRP is a continuous metric bounded by zero with a long tail of high values (right-skewed), thus requiring median/IQR to avoid outlier bias. ACR20 is binary nominal data effectively summarized by frequencies. The Patient Global Assessment is ordinal data since it features sequentially ordered categories without uniform spacing. Hemoglobin represents classic normal continuous data that is symmetrically distributed, making it appropriate for summary via mean and standard deviation.
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Anahtar Kavram
Selection of appropriate descriptive statistics and graphical displays depends directly on the data type (nominal, ordinal, continuous) and the shape of its statistical distribution (normal vs. skewed).