Table 3: Results of coefficient of association between each control variables and GHQ-12 ( 𝑁 = 7 2 8 ).

VariablesGHQ-12(1)
Low riskHigh riskCoefficient of association(2) 𝑃 value
( 𝑛 = 9 3 )( 𝑛 = 5 3 7 )

( 1 ) Sex
 Female81216−0.0510.170
 Male138293
( 2 ) Marital status
 Single751470.0530.149
 Married144362
( 3 ) Education
 Junior college or vocational school equivalency degree1212800.0020.952
 University graduate or higher98229
( 4 ) Type of job
 Clerical post27540.061(3)0.258
 Computer technical support191445
 Managerial post110
( 5 ) Shift work
 Shift work with night shifts791730.020 0.588
 Without night shifts140336
( 6 ) Average working hours per day
 Nine hours or less1904140.066 0.074
 Ten hours or more2995
( 7 ) Frequency of working on days off per month
 None1883937.084 0.008
 More than one day per month31116

(1)High risk is those who scored 4 or more when the cut-off point of the GHQ-12 was 3/4. Low risk is those who scored 3 or less.
(2)Phi coefficient.
(3)Cramer's measure of association.