Sleep, school performance, and a school-based intervention among school-aged children: a sleep series study in China.

PLoS One · 2013 · PMC3707878 · PMID 23874468

Europe PMC DOI

hedged sentence

—

closest p

—

boldest claim

The sentences

showed a trendno p-value reported

Over the past century, sleep duration in children and adolescents showed a trend of 0.75 min less per year [2] .

also in 53,322 other papers

Quoted from the open-access full text in Europe PMC under the licence the publisher applied. The sentence is reproduced exactly as published; the emphasis is ours.