The characteristics of the tested variables were started from descriptive statistics. The mean, standard deviation, skewness and kurtosis, minimum and maximum values were determined, and then the distribution of results and the coefficient of variation - group differentiation were checked in the Shapiro-Wilk test. The analysis of the obtained data was started by checking the intensity of general strain, social control, differential association and the manifestation of delinquency and antisocial behavior in both youth groups, including the sex factor.
Characteristic of general strain in the studied groups of adolescents
On the basis of the obtained results, it was found that the average result of the general strain in the research group was 82.89 (SD = 20.60, kurtosis = .21, min = 43, max = 140, V = 28.85, Shapiro-Wilk test result = 0.99, p = .16). In the control group, the mean general feeling of strain was 70.60 (SD = 17.77, kurtosis = .17, min = 41, max = 124, V = 25.17, Shapiro-Wilk test result = .95, p < .01). The coefficient of variation (V from 20 to 40%) indicated that the youth from the research and control group are moderately differentiated from the general feeling of strain. In addition, it was found that appurtenance to the group significantly differentiates youths from the general feeling of strain. The average prevalence of the general sense of strain in the research group (mean rank = 157.27) is statistically higher (U Mann-Whitney U test result = -5.04, p < .01) compared to the control group (mean rank = 109.73). Subsequently, using the non-parametric U Mann-Whitney test, the data was analyzed to determine whether appurtenance to the group significantly differentiates the studied youths of the severity of individual types of strain. The obtained results allowed to conclude that appurtenance to the group significantly differentiates the youths from both groups (p < .01) terms of the average severity of six out of seven strain scales.
In the research group, statistically significant domination of strain types were found relating to: Negative Life Events (Z = -9.72, p < .01); Life Hassles (Z = -7.04, p < .01); Negative Relations with Adults (Z = -4.26, p < .01); Parental Fighting (Z = -7.70, p < .001) and Neighbourhood Problems (Z = -4.28, p < .01). In the control group, only one higher strain level was found regarding Occupational Strain (Z = -0.43, p < .01) in comparison with the research group. However, there were no differences found between the studied groups of adolescents in terms of the intensity of the sense of strain in the area of Unpopular with Opposite Sex (Z = -2.57, p = .67) what can be understood that in both groups of studied youth the strain resulting from the lack of a sense of physical attractiveness occurs at a similar level.
Subsequently, the analyzes were made to obtain information on existing differences in the area of strain scales under consideration, taking into account the sex factor. For this purpose, the strength of eta-square effects (ƞ²) has been calculated. The collected information showed the significant effect of sex and the effect of group and sex interaction in relation to the following strain scales: negative life events, negative relations with adults, neighborhood problems, and unpopular with the opposite sex.
In the first place, it was decided to check whether appurtenance to the group and the sex of the studied youth differentiate the severity of Negative Life Events scale. On the basis of the results obtained in the research group, only a statistically significant sex effect was recorded (F (1.262) = 13.822, p < .001; ƞ² = .050) explaining 5% of observed variability. The strength of the recorded effect was weak, as indicated by the coefficient ƞ². Regarding the Negative Relations with Adults scale the obtained results gave grounds for finding significant differences in all four analyzed averages. The mean prevalence of negative relations with adults among girls from the research group (M = 5.63, SD = 2.29) in comparison with girls from the control group (M = 4.62, SD = 1.75) is higher at the level of significance of p = .015. Similarly among boys from the research group (M = 6.98, SD = 2.66) in comparison with boys from the control group (M = 5.63, SD = 1.99) at a statistically significant level p < .01. The average prevalence of negative relations with adults among boys from the research group in comparison with girls from the same group is higher at the significance level p = .01, while in the control group the analogical difference is significant at the level p = .01. Based on the above results, it can be concluded that negative relations with adults are relatively more frequent among youth from the research group (M = 6.45, SD = 2.60) compared to the control group (M = 5.13, SD = 1.94). Higher average of the occurrence of negative relations with adults is characterized by the boys' population (M = 6.36, SD = 2.46) from both studied groups than girls (M = 5.07, SD = 2.06) from these groups. On the basis of the eta-square value, the sex effect (F (1,262) = 18.063, p < .001, ƞ² = .064) was found to be statistically significant, accounting for 6.4% of the observed variability. Impact of the group was found at the same level explaining 6.5% of the observed volatility.
Summing up the findings to date regarding negative life events in relation to the research and control group, it can be stated that the overall result on the strain scale differentiates the studied groups only by the belonging to a peer group. The level of sense of strain associated with negative life events in the research group is significantly higher (F (3.262) = 55.251; R = .174; p < .001) compared to the control group. The group effect explains 17.4% of the variance. It was also found that the sex of the studied youth did not directly differentiate the level of sense of tension associated with negative life events, nor moderate the group's impact on the sense of strain.
Subsequently, the scale of Neighborhood Problems was analyzed. Analysis by pairwise comparison using the Bonferroni test showed significant differences between girls from the research and control group (p = .002) and between boys from both groups (p = .001). The obtained data also gave grounds for finding that in boys and girls from the research group problems in the immediate environment are more common (M = 7.20, SD = 3.51) than among their peers from the control group (M = 5.41, SD = 2.26). There were no significant differences between the sexes in both groups (p > .05). There were only weak relationships between the sexes in the research group (p = .078) and the control group (p = .061). Analysis of the obtained average of neighborhood problems in the closest environment also gives grounds for stating that this phenomenon is more common in general among boys from both groups (M = 6.80, SD = 3.43) than among girls (M = 5.68, SD = 2.45). Based on the calculated eta - square effect (ƞ²), a significant gender effect was found (F (1.262) = 6.675, p = .01, ƞ² = .025), which gives grounds for finding that sex (explains 2.5% of observed variability) statistically significantly differentiates the average of neighborhood problems among the studied youth from both groups.
With regard to the next dimension of strain: Unpopular with Opposite Sex. No significant differences were found between the groups of studied youth. In the research group, no intergroup difference was found regarding sex factors between boys and girls. The pairwise comparisons used showed that the strain level associated with low physical attractiveness is significantly higher (p = .02) among girls from the control group compared with boys from the same group. Based on the eta – square effect, no statistically significant sex effect was found. However, there was a weak relationship at the level of trends (F (1.262) = 3.339; p = .069; ƞ² = .013). The level of this dimension of strain is slightly (at the tendency level) higher among girls from the control group compared with girls from the research group (p = .68).
Characteristic of social control in the studied groups of adolescents
The data was analyzed to determine whether there are differences between the groups of adolescents in relation to the social control variable. Based on the obtained data, it was found that the average result of the lack or low social control in the research group amounted to 99.49 (SD = 20.29, kurtosis − .21, min = 57.50, max = 149, V = 20.39; Shapiro-Wilk test result = .98, p = .09). In the control group, the average result of lack of social control amounted to 89.79 (SD = 20.07, kurtosis = .00, min = 53.50, max = 144, V = 22.35, Shapiro-Wilk test result = .96, p < .01). The obtained data also gave grounds to claim that in the area of lack or low social control, boys and girls from the research group do not differ significantly between each other (Z = − 0.38, p = .70). Similar results were obtained relative to the control group (Z = − 0.11; p = 0.91). The coefficient of variation (V from 20 to 40%) indicated that studied youths from the research and control group are moderately differentiated from the lack of social control.
Detailed analysis of individual social control scales gave grounds to believe that appurtenance into the group (research vs control) significantly differentiates the studied youths in all social control scales (p < .01). The average of the lack or low social control in the research group is statistically higher (average rank = 152.28, Z = -3.98, p < .01) compared to the control group (average rank = 114.72). A detailed analysis of the average ranks of individual scales of social control showed that young people from the research group show significant statistical intensification of lack or weak social control. These relate to: Parental Attachment (Z = -6.25, p < .01), Parental Permissiveness (Z = -5.29, p < .01), School Attachment (Z = -9.41, p < .01), Grades (Z = -14.12, p < .01). In the control group, a statistically higher average was found the for scales: Peer Attachment (Z = -2.85, p < .01) and Time Spent on Homework (Z = -19.71, p < .01).
In order to study the differentiating sex, group and interactive effect of the group and sex of the social control scales, two-factor analysis of variance was used in the intergroup scheme among the studied youth. A significant effect of sex, group and sex interaction was found on only one scale regarding School Attachment. In relation to this scale, statistically significant differences were found between girls and boys in both studied groups at the level of p < .001 and between girls and boys from research group (p = .004). Lack of satisfaction with the fact of staying at school and the conviction that graduation will not be of any importance in the future is higher in the research group, especially among boys. The overall results also showed that the studied boys' population (M = 18.44) from both groups shows a higher level of this variable than girls (M = 16.08) from both groups combined.
Subsequently, the analyzes were made to obtain information on existing differences in the area of social control scales under consideration, taking into account the gender factor. For this purpose, the strength of eta-square effects has been calculated. The collected data showed the significant effect of sex and the effect of group and sex interaction in relation to the following social control scales: School Attachment, Grades and Time Spent on Homework.
Regarding the scale of School Attachment, only the group effect was obtained. A detailed analysis of the obtained average incidence of dissatisfaction with being at school gave grounds to conclude that youths from the research group (M = 20.59, SD = 4.56) much more often than youths from the control group (M = 14.19; SD = 4.60) is characterized by low attending school satisfaction. The group effect (F(1.262) = 9.296, p = .003, ƞ² = .034) explaining 3.4% of the observed variation turned out to be statistically significant.
In further analyses, attempts were made to determine the average of class repetitions in both the research and control groups. Based on the obtained data, it was established that in the research group, class repetitions is higher amongst girls (M = 2.56, SD = 1.74, p < .001) than boys (M = 1.92, SD = 1.92). In the control group, no significant differences were found between girls and boys (p > .05). Based on the eta-square partial value, significant was determined sex effect (F(1.262) = 7.024, ƞ²= 0.26; p < .05) responsible for 26% of the observed variation and the group effect (F(1.262) = 5.819, ƞ² = 0.22; p < .05) regarding 22% of the observed variation, which can be interpreted as that both sex and group membership (research vs control) significantly statistically differentiates the respondents due to the number of class repetitions.
The analysis of the data obtained, referring to the Time Spent on Homework showed that the youth of both sexes from the control group spend statistically significantly (p < .001) more time on homework than youth from the research group. In the control group, girls spend more time for homework (M = 13.36, SD = 7.82, p = .002) than boys (M = 10.37; SD = 6.11). The sex effect turned out to be significant (F(1,262) = 8,056; p = .005; ƞ² = 0.030) explaining 3% of the observed variation, which means that sex differentiates youth because of the time spent on homework. In the research group no differences were found between boys and girls (girls M = 3.27, SD = 4.24; boys M = 2.30, SD = 3.29, p > .05).
Characteristic of differential association in the studied groups of adolescents
Regarding to the Friends' Delinquency variable data were obtained showing that the average result in the research group was 15.02 (SD = 3.97, kurtosis = .21, min = 5, max = 20, V = 26.43, Shapiro-Wilk test result = .93, p < .01). Among girls from the research group, the average was 16.34 (SD = 3.36), while among boys 14.04 (SD = 4.03). This data gives grounds for stating that girls from the research group (Z = -3.76, p < .01) make contacts with friends displaying traits of social maladjustment, demoralization, involvement in crime, alcoholism and drug addiction, significantly more often than boys. In turn, in the control group, the mean severity of this variable was 8.48 (SD = 3.39, kurtosis = .21, min = 5, max = 19, V = 39.98, Shapiro-Wilk test result = .88, p < .01). Among girls, the average was 8.00 (SD = 3.19), among boys 8.96 (SD = 3.54). These data provide grounds for stating the absence of a statistically significant difference between the two sexes (Z = -1.70, p = .09). The coefficient of variation (V from 20 to 40%) indicates that studied youths from the research and control group are moderately differentiated in maintaining engaged contacts with a wide range of delinquent and drug-use friends. The average contact with friends displaying behaviors of social maladjustment, demoralization, involvement in crime, alcoholism and drug addiction in the research group is statistically higher (average rank = 184.26, Z = -10.79, p < .01) in comparison with a control group (average rank = 82.74). Also, the data suggested that the differences between the groups are significant for both sexes was also obtained (p < .001). Boys from the research group significantly more often than boys from the control group are characterized by maintaining contacts with friends violating legal and social norms. A similar situation was found between girls from the research and control group. Based on the eta coefficient, the interaction of group and gender was found (F (1.262) = 15.898, p < .001, ƞ²= .057), which accounts for 5.7% of the observed variation.
Characteristics of delinquent behavior and violating social norms in the studied groups of adolescents
Based on the data, it was found that the average result of delinquent behavior in the research group amounted to 94.67 (SD = 46.80). Among girls from the research group, the average result of delinquent behaviors was 106.54 (SD = 47.82), while among boys 87.05 (SD = 44.76). In the control group, the average result of antisocial behavior was 13.30 (SD = 16.34), among girls 7.18 (SD = 7.24), and boys 19.33 (SD = 20.20). The empirical data collected on manifestations of criminal behavior and violating social norms in the research group and violating social norms in the control group unambiguously gave grounds for stating that belonging to the group significantly differentiates the persons examined in relation to the antisocial behaviors they undertake. The average of behaviors that violate legal and social norms (Z = -13.29, p < .01) is statistically higher in the criterion group. In addition, it was found that in the intensity of antisocial behavior undertaken, boys and girls from the research group differ significantly. The girls from the research group, compared to the boys from this group, are characterized by a significantly higher average of delinquent behaviors (Z = -2.32, p < .05). In the control group, boys had a higher average of behavior that violates social norms than girls (Z = -4.42, p < .01).
In order to check the existing differences between manifestations of antisocial behavior between the studied groups of adolescents, the Mann-Whitney U test has been used. The general results regarding the average ranks of behavior in both groups of subjects showed the existence of statistically significant differences in all forms of antisocial behavior with their significant advantage in the research group. These behaviors include: participation in a physical violence (Z = -11.52, p < .01), participation in the robbery (Z = -10.33, p < .01), theft of small items up to $20 (Z = -13.00, p < .01), stealing valuable things, e.g. cars, jewellery (Z = -12.57, p < .01), burglary (Z = -10.62, p < .01), acts of vandalism (Z = -11.93, p < .01), staying out of school (Z = -8.62, p < .01), escape from home (Z = -10.08, p < .01), drinking alcohol (Z = -7.49, p < .01), using marijuana (Z = -11.87, p < .01), using LSD, amphetamine, heroin (Z = -11.18, p < .01), participation in assault (Z = -12.70, p < .01), selling drugs (Z = -9.90, p < .01), hitting of a teacher (Z = -5.56, p < .01), parental abuse (Z = -4.24, p < .01), self-injurious behavior (Z = -8.34, p < .01), suicide attempts (Z = -7.09, p < .01), hitting someone without a specific reason (Z = -8.01, p < .01), psychological abuse of weaker colleagues (Z = -8.63, p < .01), physical abuse of weaker colleagues (Z = -8.35, p < .01), animal abuse (Z = -4.67, p < .01), scaring others with weapons or other sharp tools (Z = -8.55, p < .01).
The above data allowed to confirmed that sex and appurtenance to the group significantly differentiates studied youth in the field of behaviors that violate legal and social norms. The obtained empirical data confirmed a statistically significant difference (p < .001) in the occurrence of delinquency behavior and violating social norms in the studied groups, with the prevalence of their occurrence in the research group.
Correlations among strain, social control, differential association, and youth delinquency
In the further course of the research, attempts were made to determine the existing relationships between the represented general sense of strain (and its types), social control, differential association and behaviors violating legal and social order in the research group and behaviors violating social norms in the control group. For this purpose, the analysis of R-Spearman’s correlation coefficients was used. The analysis of the results obtained, included both groups of studied youth, gave grounds for establishing no significant correlations between the general sense of strain, social control and behaviors violating legal and social norms in the research group and behaviors violating social norms in the control group (Table 1 here).
TABLE I. Correlations among General Strain, Social Control, Differential Association, and Youth Delinquency
In addition, the obtained results gave the basis for the statement that in both groups of the studied youth maintaining contact with friends who exhibit behaviors indicating social maladjustment, demoralization, involvement in crime, alcoholism and drug addiction at a statistically significant level (p < .01) correlates with behaviors violating legal and social norms in both study groups.
The further analyzes show correlations related to individual strain scales, social control and differential association. The obtained results are shown in Table 2.
In the light of the presented results regarding strain measure, it was found that the greater the severity of negative life events in adolescents’ lives, the more likely they are to take exhibit behaviors that violates legal and social norms (R = .23, p < .01). In the area of social control measure, data was obtained suggesting that the lower intensity of satisfactory peer attachment (R = − .18, p < .05) and the low amount of time spent on homework (R = − .24, p < .01) corresponds to the greater intensity of undertaken behavior violating legal and social norms. Similar results were obtained relative to the differential association measure, suggested that increased contact with friends displaying behaviors demonstrating social maladjustment, demoralization, involvement in crime, alcoholism and drug addiction, the more likely the research group are exhibit behaviors violating legal and social norms (R = .49, p < .01).
In the control group, correlations were obtained that concluded the higher the severity of negative relationships with adults (teachers, parents), the higher the likelihood among students to engage in behavior that violates social norms (R = .23, p < .01). In the scope of the social control measure, it was found that there was lower school attachment. Similarly there was lower belief that school completion would pay off in the future. This was accompanied by an average higher level of involvement in behavior violating social norms (R = − .18, p < .05). As in the research group, among students from the control group, the correlation obtained gave grounds to believe that the higher the level of contacts with friends displaying behaviors demonstrating social maladjustment, demoralization, involvement in crime, alcoholism and drug addiction in students’ lives, the higher the likelihood of involvement in behavior violating social norms (R = .34, p < .01).
Analysis of correlations between variables in the regression model
Similarly to Agnew and White research (1992), stepwise regression analysis was performed, in which delinquent behavior and antisocial were determined as the dependent variable. The variables examined included sex, age, group, strain scales, social control scales and differential association scale. The use of stepwise regression analysis in relation to the research group allowed (after elimination of insignificant predictors) to introduce only independent variables into the model that significantly predict the dependent variable. The obtained results are presented in Table 3.
In the research group, after adjusting R² = 0.172, the model turned out to be relevant for only one predictor: Friends’ Delinquency (Beta = .422). The model proved to be well suited to the data (F(1,131) = 28,248; p < .001). This variable explains 17.2% of the variance of the dependent variable among youth from the research group. The correlation between variables is strong and positive. Based on the obtained regression result, it can be stated that only one predictor most significantly predicts retaining violating legal and social norms among adolescents from research group. This justifies the conclusion that the increase in contact with friends displaying behaviors indicating social maladjustment, demoralization, and involvement in crime, alcoholism and drug addiction predicts an increase in the intensity of behaviors that violate legal and social norms among adolescents from the research group. The above correlation can be understood as significant, which fully confirms Sutherland's thesis that criminal behavior is a learned behavior, and the learning of criminal behavior itself occurs in the course of interaction with other people in the communicative process and that a substantial part of learning criminal behavior takes place in within primary groups.