in this study , we gathered the total sample size is 200 of mentally retarded students in north of tehran ( districts 1 , 2 , 3 ) and the sample size was determined according to previous research ( 11 - 12 ) and also sample size for preliminary evaluation of reliability and validity test .
data were analyzed by cronbach 's alpha coefficient for internal consistency and linear multivariate regression for construct validity ( since this scale has seven items and each item measures comments and feedback of the person about one area of personal well - being , the designers ( 16 ) of this scale believe that the individual score in each area plays an important role in the distribution of overall life satisfaction scores ( the first single item and separated from the other seven items ) .
therefore , the designers have recommended linear multivariate regression analysis for validity assessment in which individual score in single item of overall life satisfaction as the dependent variable and the seven items scales as prediction variables are considered ) . after obtaining an authorization for the study from tehran 's exceptional education organization
, we referred to sayyad shirazi girl 's exceptional school and piroozi boy 's exceptional school located in north of tehran . in these schools , a total of 200 mentally retarded students were selected of morning shift from 8 to 12 and afternoon shift from 2 to 5 and were studied in the counseling room . during this period , eight meetings with the mothers were held before research on their children and after describing the aims of the research , all mothers signed a written consent form .
the test in this research was the personal well- being index- cognitive disability scale ( 16 ) that was conducted for mentally retarded students.this indicator consists of five stages . at the beginning of the test
, some questions are asked about agreement responses that determine whether the student should continue the test or not .
if the student succeeds , he/ she will enter the next stage which is the testing of likert scale sufficiency and the student should numerate from zero to ten.then , the student enters the total happiness scale of personal well- being index that consists of eight questions in two parts .
the first part asks about life satisfaction : are you satisfied with your life ? ; and the second part consists of questions regarding the following issues : 1 ) life standards and conditions ; 2 ) health ; 3 ) achievements in life ; 4 ) relationships with others ; 5 ) safety and peace in life ; 6 ) dependence and membership among others ; 7 ) future safety.the student responses to each of the eight items with likert scale of zero to ten , with each number showing the following states : zero : completely dissatisfied and sad ; five : average ; ten : completely satisfied and happy ; between zero and five : completely dissatisfied and sad to average ; and between five and ten : average to completely satisfied and happy . if the student does not succeed at the likert scale stage , another three stage test will be used for him which ( cube test ) consists of three two  cube , three- cube and five- cube stages .
the fourth stage is to match with the abstract reference ( step building by cubes ) that consists of three stages : two steps , three steps and five steps .
the fifth stage is to match with the abstract reference ( images stage ) in which the child shows his / her satisfaction in each item with regard to the images ( two faces , three faces and five faces ) ( 16 ) .
the construct validity of this indicator questions was 0.78 with respect to satisfaction scale ; and according to 12 studies conducted in australia , the maximum changes of the reliability was 3.1 percent of personal well- being and in australia and other world regions , cronbach 's alpha coefficient was 0.70- 0.85(16).the correlation between the questions was 30%-55% and the sum of questions correlation was at least 50% in pwi - a version ( 10 ) .
all the questions of personal well - being index- cognitive disability were translated and revised based on ( comqol ) and pwi protocol .
then , the translated text was back translated , and the two forms were compared .
finally , the translated text was revised and given to several professors holding a phd in psychology ; and their professional suggestions were included in the translations . to identify the face validity and initial survey , the persian version of the personal well - being index- cognitive disability scale
in this study , we gathered the total sample size is 200 of mentally retarded students in north of tehran ( districts 1 , 2 , 3 ) and the sample size was determined according to previous research ( 11 - 12 ) and also sample size for preliminary evaluation of reliability and validity test .
data were analyzed by cronbach 's alpha coefficient for internal consistency and linear multivariate regression for construct validity ( since this scale has seven items and each item measures comments and feedback of the person about one area of personal well - being , the designers ( 16 ) of this scale believe that the individual score in each area plays an important role in the distribution of overall life satisfaction scores ( the first single item and separated from the other seven items ) .
therefore , the designers have recommended linear multivariate regression analysis for validity assessment in which individual score in single item of overall life satisfaction as the dependent variable and the seven items scales as prediction variables are considered ) .
after obtaining an authorization for the study from tehran 's exceptional education organization , we referred to sayyad shirazi girl 's exceptional school and piroozi boy 's exceptional school located in north of tehran . in these schools , a total of 200 mentally retarded students were selected of morning shift from 8 to 12 and afternoon shift from 2 to 5 and were studied in the counseling room . during this period , eight meetings with the mothers were held before research on their children and after describing the aims of the research , all mothers signed a written consent form .
the test in this research was the personal well- being index- cognitive disability scale ( 16 ) that was conducted for mentally retarded students.this indicator consists of five stages . at the beginning of the test
, some questions are asked about agreement responses that determine whether the student should continue the test or not .
if the student succeeds , he/ she will enter the next stage which is the testing of likert scale sufficiency and the student should numerate from zero to ten.then , the student enters the total happiness scale of personal well- being index that consists of eight questions in two parts .
the first part asks about life satisfaction : are you satisfied with your life ? ; and the second part consists of questions regarding the following issues : 1 ) life standards and conditions ; 2 ) health ; 3 ) achievements in life ; 4 ) relationships with others ; 5 ) safety and peace in life ; 6 ) dependence and membership among others ; 7 ) future safety.the student responses to each of the eight items with likert scale of zero to ten , with each number showing the following states : zero : completely dissatisfied and sad ; five : average ; ten : completely satisfied and happy ; between zero and five : completely dissatisfied and sad to average ; and between five and ten : average to completely satisfied and happy .
if the student does not succeed at the likert scale stage , another three stage test will be used for him which ( cube test ) consists of three two  cube , three- cube and five- cube stages .
the fourth stage is to match with the abstract reference ( step building by cubes ) that consists of three stages : two steps , three steps and five steps .
the fifth stage is to match with the abstract reference ( images stage ) in which the child shows his / her satisfaction in each item with regard to the images ( two faces , three faces and five faces ) ( 16 ) .
the construct validity of this indicator questions was 0.78 with respect to satisfaction scale ; and according to 12 studies conducted in australia , the maximum changes of the reliability was 3.1 percent of personal well- being and in australia and other world regions , cronbach 's alpha coefficient was 0.70- 0.85(16).the correlation between the questions was 30%-55% and the sum of questions correlation was at least 50% in pwi - a version ( 10 ) .
all the questions of personal well - being index- cognitive disability were translated and revised based on ( comqol ) and pwi protocol .
then , the translated text was back translated , and the two forms were compared .
finally , the translated text was revised and given to several professors holding a phd in psychology ; and their professional suggestions were included in the translations . to identify the face validity and initial survey , the persian version of the personal well - being index- cognitive disability scale
two hundred mentally retarded students had a minimum age of 9 and a maximum age of 21 years and their mean age was 14.49  2.66 .
demographic characteristics of mentally retarded students cronbach 's alpha coefficient the seven items of personal well - being index- cognitive disability was between 0.56 - 0.62.besides , studying the internal consistency of these items showed that all the seven items were correlated with the total score and their scores averages were similar to each other .
this indicates that the test 's questions have reliability with regard to evaluation of a common feature .
cronbach 's alpha for mentally retarded students it should be mentioned that one hundred of mentally retarded students participated in test - retest reliability study .
the results are presented in table 3 . also , the results of coefficients test - retest using the pearson correlation between initial and retest scores were significant at 0.001 level . 
 
coefficient alpha and test - retest results of kmo and bartlett 's test showed that the sample size was sufficient for analysis .
bartlett test of sphericity resulted in a chi - square value of equal to 818.974 with 406 degrees of freedom that was significant in an alpha level of 0.001 .
as previously mentioned , since this scale has seven items and each item measures comments and feedback of the person about one area of personal well - being , the designers of this scale believe that the individual score in each area plays an important role in the distribution of overall life satisfaction scores ( the first single item and separated from the other seven items ) .
therefore , the designers have recommended linear multivariate regression analysis for validity assessment of personal well - being index - cognitive disability ( 16 ) in which individual score in single item of overall life satisfaction as the dependent variable and the seven items scales as prediction variables are considered .
and results of linear multivariate regression analysis with enter method showed that the scale items can predict 67% of distribution of overall life satisfaction . 
 
anova - linear multivariate regression by enter method for mentally retarded students besides , there was a significant relation between the questions of part one and the questions of part two , after implementation of linear multivariate regression analysis , regression coefficients were calculated for the seven items and the results showed that the among the seven items of personal well - being index- cognitive disability scale , items 2 and 7 has significant contribution to the prediction of satisfaction with life in mentally retarded students in north of tehran . 
 
cronbach 's alpha coefficient the seven items of personal well - being index- cognitive disability was between 0.56 - 0.62.besides , studying the internal consistency of these items showed that all the seven items were correlated with the total score and their scores averages were similar to each other .
this indicates that the test 's questions have reliability with regard to evaluation of a common feature .
cronbach 's alpha for mentally retarded students it should be mentioned that one hundred of mentally retarded students participated in test - retest reliability study .
the results are presented in table 3 . also , the results of coefficients test - retest using the pearson correlation between initial and retest scores were significant at 0.001 level . 
 
coefficient alpha and test - retest results of kmo and bartlett 's test showed that the sample size was sufficient for analysis .
bartlett test of sphericity resulted in a chi - square value of equal to 818.974 with 406 degrees of freedom that was significant in an alpha level of 0.001 .
as previously mentioned , since this scale has seven items and each item measures comments and feedback of the person about one area of personal well - being , the designers of this scale believe that the individual score in each area plays an important role in the distribution of overall life satisfaction scores ( the first single item and separated from the other seven items ) .
therefore , the designers have recommended linear multivariate regression analysis for validity assessment of personal well - being index - cognitive disability ( 16 ) in which individual score in single item of overall life satisfaction as the dependent variable and the seven items scales as prediction variables are considered .
and results of linear multivariate regression analysis with enter method showed that the scale items can predict 67% of distribution of overall life satisfaction . 
 
anova - linear multivariate regression by enter method for mentally retarded students besides , there was a significant relation between the questions of part one and the questions of part two , after implementation of linear multivariate regression analysis , regression coefficients were calculated for the seven items and the results showed that the among the seven items of personal well - being index- cognitive disability scale , items 2 and 7 has significant contribution to the prediction of satisfaction with life in mentally retarded students in north of tehran . 
 
this is the first study which evaluates the validity and reliability of the personal well - being index- cognitive disability on mentally retarded students in north of tehran .
the results confirmed the reliability and validity for the personal well - being index- cognitive disability in mentally retarded students of exceptional schools in north districts of tehran .
findings of this study are relatively harmonious with studies of lau and cummins ( 10 ) , miller ( 12 ) , davey ( 17 ) and davern ( 18 ) . also , the results of this study is relatively harmonious with that of diener , emmons , larsen , griffin ( 13 ) and tomas ( 14 ) , which reported a correlation of 0.78 between the satisfaction and life scale .
lau and cummins ( 10 ) reported the eight domains form to be a single stable factor which accounts for about 50% of the variance in australia and other countries .
overall , pwb is an important construct , as its low levels can lead to depression or social isolation ( 19 , 20 ) . in this
regard , identification of factors that maintain high levels of swb such as community connectedness are important for developing strategies to prevent problems associated with low levels of swb . with regard to the extracted data from the results of this research , it can be concluded that mentally retarded students in north districts of tehran had lower emotional , mental and behavioral and , in general , improper reactions to the environmental and social desirable stimulus .
therefore , using efficient and effective strategies and ability of researchers to control interfering factors have resulted in validity and reliability of this indicator in north districts of tehran . in addition , the studied children and teenagers have experienced similar mental conditions , family and economic stresses and similar environmental conditions .
they accepted the facts and tried to solve their problems , engaged in group programs such as collective game , expression of events , memoirs and short stories and interacted with friends and got involved in physical activities and cognitive programs such as counting digits down , and also sports .
further , they were not disappointed with undesirable attitude and response of people and society .
they , with a heart full of hope , did not think about their weaknesses and disabilities and tried to see a light in the darkness and tried to be active and dynamic and to think about their capabilities .
parents respect increased these children 's self- respect and created internal security and emotional immunity against cultural and social plagues .
in general , it can be concluded that the personal well - being index- cognitive disability on mentally retarded students of north districts of tehran is a valid and reliable scale .
therefore , we suggest that the experts of exceptional education and psychology clinics to use this index to identify the well - being of mentally retarded students .
as a limited group of mentally retarded students were enrolled in this study , these findings can not be generalized .
 objectivehaving a good quality of life has always been desirable for humans , and the concept of a good life and the ways of achieving it have become important over the years . 
 personal wellbeing is the mental component of quality of life . 
 thus , the current study was conducted to assess the reliability and validity of the   personal well - being index- cognitive disability on mentally retarded students.method200 mentally retarded students in north districts of tehran ( districts 1 , 2 and 3 ) were selected by systematic random sampling . 
 the collected data using personal well - being index- cognitive disability was analyzed by cronbach 's alpha coefficient for internal consistency and linear multivariate regression for construct validity.resultsresults confirmed the reliability and validity for the personal well - being index- cognitive disability in mentally retarded students of exceptional schools . studying the internal consistency of seven items showed that all the items were correlated with the total score and their scores averages were similar to each other . 
 this indicates that the test 's questions have reliability with regard to evaluation of a common feature and results showed personal well - being index- cognitive disability had the most extensive coverage of construct validity.conclusionpersonal well - being index- cognitive disability scale could be applied to measure personal wellbeing in mentally retarded students . 
Material and Methods
Participants and Statistical analysis
Procedure
Instruments
Result
Reliability Criteria
Construct Validity
Discussion
Limitations