Accumulation of wear and tear in archival and library collections. Part II: an epidemiological study

Heritage Science

Table 2 Results of t-tests and descriptive statistics on the percentage of failed sheets within an inventory number grouped by number of requisitions in the reading room since 1998 and prior owner

Exposure variable	Outcome variable: failed sheets (%)			n	95% CI for mean difference	t	df	p
Exposure variable	M	SD	SE	n	95% CI for mean difference	t	df	p
Reading room < 8×	18.1	25.6	2.2	136	− 25.1, − 9.9	− 4.58	100	< 0.001
Reading room ≥ 8×	35.6	22.2	3.1	50	− 25.1, − 9.9	− 4.58	100	< 0.001
Owner: private	25.3	28.6	3.0	94	− 2.3, 12.6	− 1.37	176	0.173
Owner: government	20.2	22.6	2.4	92	− 2.3, 12.6	− 1.37	176	0.173

M, mean; SD, standard deviation; SE, standard error of the mean; n, number of observations; CI, confidence interval; t, t test; df, degrees of freedom; p, p value