A Novel Method for Air Quality Data Imputation by Nuclear Norm Minimization

Table 2

Descriptive statistics.

Statistics	Percentage of missing values
	10%	20%	30%	40%	50%
Number of valid values	9043	8056	7058	6010	4989
Number of missing values	989	1976	2974	4022	5043
Mean	128.62	128.08	128.23	127.63	128.20
Standard deviation	69.69	69.72	69.54	69.39	69.42
Skewness	0.2581	0.2611	0.2477	0.2467	0.2448
Kurtosis	2.4551	2.4469	2.4409	2.4347	2.4372
Range	338	338	338	338	338
Maximum value	348	348	348	348	348
Minimum value	10	10	10	10	10