CHAPTER THREE
3.5 Sampling procedures
3.5.1 Study population
In Nigeria, learners spend six years in primary schools and six years in secondary schools. At the primary level, there are six levels according to the years of study – primary 1 to 6. Each primary level is made up of a number of classes. The six years spent in secondary level are divided into two phases: Junior Secondary School and Senior Secondary School. A student takes three years to complete each level.
At the junior level, there are three categories according to the year of study:
Junior Secondary School (JSS) 1
Junior Secondary School (JSS) 2
Junior Secondary School (JSS) 3
At the senior level, there are also three categories signifying the years of study:
Senior Secondary School (SSS) 1
Senior Secondary School (SSS) 2
Senior Secondary School (SSS) 3
Each of JSS 1-3 and SSS 1-3 is then made up of a number of classes.
Oyo State is divided into eight educational zones: Ibadan City; Ibadan Less City; Ibarapa;
Ogbomoso; Oyo; Saki; Kajola; and Irepo. According to information obtained from the Oyo State Ministry of Education, there were 14 special schools that trained IIL in six of the eight educational zones, excluding Ibarapa and Irepo, with an enrolment of 1,025 IIL from all
156 categories at the time of the study (567 [55.3%] boys and 458 [44.7%] girls) (see Table 1).
However, one more school, which was not on the list provided by the Ministry of Education, was discovered in the Oyo educational zone during fieldwork. Therefore, this school was not included in the study. In addition, one of the special schools in Ibadan City was used in the pilot study but not included in the actual study.
There were 548 junior and 432 senior public secondary schools in Oyo State (Oyo State Government, 2009). The Oyo State Ministry of Education declined to release the actual enrolment statistics of students in its secondary schools. These schools were located all over the eight educational zones in the state. Four of the schools provided inclusive education for students with disability on the same premises and/or in the same classrooms. However, the few IIL enrolled in such schools were separated into different classrooms due to their special education needs.
The age group studied (12-19 years) was mostly found at the primary level of education for IIL and at the secondary level of education for ML. Because of their cognition impairment, IIL seldom reach the secondary level and, as such, only a few of them (27) were enrolled in four secondary schools that offered inclusive education in the state at the time of this study. They were excluded from the study because they were not at the same educational level as most of the IIL in the state, and their exposure to HIV/AIDS and sexuality education might have been different.
The study population was made up of mild/moderate intellectually impaired and mainstream learners aged 12-19 years in the 13 public special schools (primary) and nearby regular schools.
The special schools were all located in six educational zones – Ibadan City (six schools); Ibadan Less City (one school); Ogbomoso (two schools); Oyo (one school); Kajola (one school) and Saki (one school).
157 3.5.2 Sampling strategy for the quantitative method
Due to the small number of IIL in the special schools, the study recruited every learner that met the inclusion criteria and was willing to participate in the study. This was done to be able to get a sample size that is representative of the study population (for the quantitative method). However, ML in selected schools were recruited into the study through multi-stage random sampling. A multi-stage random sampling entails selection of the primary sampling units (PSU) as the first- stage sample, and then drawing a sub-sample from each selected PSU to form the second-stage sample (Snijders, 2001). A secondary school was selected based on proximity to each of the special schools, and one class was picked randomly from each of the three junior and two senior secondary school classes. Senior Secondary School 3 (SSS 3) learners were not available because they were writing West African School Certificate Examinations at the time of the study. Participants between the ages of 12 and 19 were randomly selected from each of the five classes.
Different sampling strategies were employed in this study to be able to adequately ensure representation/inclusion of IIL. Researchers have argued in favour of striking a balance between rigorous academic research and the inclusion and/or representation of marginalised groups such as persons with intellectual impairments in research (Booth, 1996; Walmsley & Johnson, 2003;
Woodring, Foley, Rado, Brown, & Hammer, 2006; Aldridge, 2007). Therefore, some flexibility have been suggested in research involving such marginalised groups without jeopardising the quality and ethics of research while ensuring that marginalised groups do not become more marginalised by constant exclusion from research (Woodring et al., 2006).
3.5.2.1 Sample size
Group sample sizes of 257 in group one and 257 in group two achieve an 80.0% power to detect a difference of 0.11 between the group proportions (D'Agostino, Chase, & Belanger, 1988;
Fleiss, Levin, & Paik, 2003; Lachin, 2000), in respect of sexual abstinence. The proportion in group one (IIL) is assumed to be 70.0% under the null hypothesis and 81.0% under the alternative hypothesis. This was arrived at by using a previous study in South Africa (Dawood et
158 al., 2006) that found an abstinence rate of 86.0% among II adolescents and, according to available literature, this was the only study that documented such in Africa. The proportion of sexually abstinent persons in group two (ML) is assumed to be 0.70 (70.0%), based on a study in Oyo State, Nigeria, that reported 65.0% sexual abstinence among learners (I.O. Fawole, Asuzu, Oduntan, & Brieger, 1999).
To allow for multivariate analysis (especially among the sexually active respondents), the sample size was increased to 300 per group.
The test statistic used in the sample size determination is the two-sided Fisher‘s exact test. The level of the test was targeted at 0.05.
A statistician was consulted when determining the sample size.
3.5.3 Sampling strategies for the qualitative methods 3.5.3.1 FGD
Four of the six educational zones were selected for the FGDs. The six educational zones were stratified into two, based on their level of urbanisation. Three of them (Ibadan City, Oyo, and Ogbomoso) were urban and the other three (Kajola, Ibadan Less City and Saki) were less urban.
Ibadan City, Oyo, Kajola and Ibadan Less City educational zones were selected from the two strata via balloting. There was only one special school in each of the educational zones except in Ibadan City. A special school was then selected randomly for the Ibadan City educational zone.
Regular schools in the vicinity of each of the special schools were selected.
Participants were randomly selected for FGDs by asking every sixth learner if s/he was interested in participating in the study.
159 3.5.3.2 In-depth interviews
Schools were picked randomly in each of the six educational zones. Every sixth learner who met the inclusion criteria in the selected school was asked if s/he was interested in participating in the interview. Two learners were then selected by balloting among those who were interested.
Twelve IIL and 12 ML participants were selected using this procedure.
3.5.3.3 Key informant interviews
Teachers were recruited for the study based on recommendations of the head teachers or principals. After explaining the purpose of the study to the head teacher/principal, s/he was asked to recommend a teacher who was familiar with the subject. In the case of teachers of IIL, teachers in charge of the IIL classes were selected for the study. When such teachers were not willing to participate, another teacher with relevant experiences was suggested by the unwilling teacher. The first teacher interviewed was then asked by the interviewer to suggest another teacher that could provide valuable information about the subject. Twelve IIL teachers and 12 ML teachers were selected overall.
3.5.4 Inclusion criteria The study included:
Only learners with mild/moderate intellectual impairments with significant limitations in adaptive behaviours, and learning in educable and trainable classes in special schools
Mainstream learners without intellectual impairments in regular schools
Learners between the ages of 12 and 19
Respondents (both IIL and ML) from the six educational zones with special schools for the training of IIL
160 3.5.5 Exclusion criteria
The following were excluded from the study:
Learners who didn‘t fall within the age range of 12-19 years
Married learners
Intellectually impaired learners with communication problems (speech difficulties) that made them unable to express themselves
The few IIL in secondary schools