What is a P value?

Researchers investigated whether rapid rather than standard intravenous rehydration resulted in improved hydration and clinical outcomes when administered to children with gastroenteritis. Treatments were compared in a parallel randomised controlled trial. Children were recruited if aged 3 months to 11 years, had a diagnosis of dehydration secondary to gastroenteritis, had not responded to oral rehydration, and had been prescribed intravenous rehydration. Intervention was rapid (60 mL/kg) or standard (20 mL/kg) rehydration with 0.9% saline over an hour.1 The primary outcome was the proportion of children with clinical rehydration, assessed on a validated scale, within two hours of start of treatment. In total, 226 children were recruited, of whom 114 were randomised to rapid and 112 to standard rehydration. The proportion of children rehydrated at two hours was higher in the rapid rehydration group, although the difference was not significant (41/114 (36%) v 33/112 (29.5%); P=0.32). Which one of the following statements best describes the P value? Statement c best describes the P value. The trial investigated whether rapid rather than standard intravenous rehydration resulted in improved rehydration and clinical outcomes when …