Independent-Samples T Test



Independent-Samples T Test

Introduction

In Howell (1958), there are various conditions where this test was used and could be used. The two different groups could be made in terms of gender variations, grades variations etc. In this study the main purpose of using the independent samples t - test is to determine the levels of ADD with respect to gender differences, and also using the different grades differences and also with respect to the IQ scores of the students.

Method

Participants

Participants were 216 students (54% boys, 46% girls) from one of 18 schools in northwestern Vermont. The schools were chosen in such a way to produce a reasonable cross section of rural schools within 40 miles of Burlington, VT. Age at first assessment, family background, racial/ethnic identity and other background variables were not assessed.

Procedure

All participants were part of a larger study conducted by Howell, Huessy, and Hassuk (1985). The original study began with 501 children in the second grade and consisted of six stages of data collection: 2nd grade, 4th grade, 5th grade, 9th grade, 12th grade, and 3 years post graduation. The first three assessments were collected via the child's current teacher, the second two assessments were collected via school records and the final assessment was an extensive interview. Due to normal attrition, the sample size was reduced to 352 children by the end of the fifth grade. The present study utilizes data collected during all six collection periods and includes only those for whom complete data is available (N = 216).

Measures

Gender. The gender of the child was collected via a questionnaire completed by the child's second grade teacher.

Grade repetition. Whether or not the child repeated a grade during high school was assessed via school records at the end of the 12th grade.

English level. The level of English class the child was enrolled in was assessed via the school record in the ninth grade. The three categories were: remedial, general and college preparatory.

English grade. The grade the child received in English during the ninth grade was assessed via school records. Grades were: A, B, C, D, or F.

Social adjustment problems. Whether or not the child exhibited any social adjustment problems in the ninth grade was assessed via school records. A child was considered to have a social adjustment problem if there were at least two notations in the record of infractions like disruptive classroom behavior, ...