: Description of the Study and Data fille A study was carried out to explore the efficacy of early intervention

Question 1 :

Description of the Study and Data fille

A study was carried out to explore the efficacy of early intervention for children with reading difficulties. Six-year-old children who had made a slow start in learning to read were assigned to either the control condition or to Reading Recovery (RR) (an early intervention for children with reading difficulties). The assignment was not random as the schools wanted to ensure that the children with the greatest difficulty got the intervention. Children were tested at the beginning of the school year and at the end. Because of the non-random way in which children were assigned to either the control or the intervention group, it is important to control for preintervention reading levels in order to evaluate the intervention.

You will need to download the SPSS data file readexam.sav from BLACKBOARD. The file readexam. sav contains the following variables:

ZPOST Reading ability at post-test. This is constructed from LIRAW2, CAPRAW2 and BASWR2, which are post-test versions of LIRAW1, CAPRAW 1 and BASWR1 (described below). Z-scores were created for LIRAW2, CAPRAW2, and BASWR2. ZPOST is the mean of these Z-scores.

LIRAW1 Score in letter identification test. The Clay test of children's ability to recognise letters (name, sound or a word beginning with the letter). Children are shown 54 letters, some upper case, some lower case plus a few letters such as ' $a$ ' and ' $g$ ' whose form changes in different fonts.

CAPRAW1 Score in concepts about print test. The Clay test of children's knowledge of the conventions of print - print and not pictures carry the message, directionality, spoken to written word correspondence, the meaning of various aspects of punctuation, etc.

BASWR1 Score in British Ability Scale Word Reading test. A standardised test of children's word reading (out of context). Children are shown a series of words of increasing difficulty and asked to read them until they make ten consecutive mistakes.

GROUP Experimental group $(0=$ Control, $1=$ Exposed to Reading Recovery)

AGE Age in months at pre-test

GENDER Gender (0= boy, 1= girl )

LANGUAGE English as 1st or 2nd language 0=1 ^st language, 1=2 ^nd language

FREEDIN Eligible for free school dinners (0= No, 1=Yes)

Task

Carry out analysis to explore the effect of Reading Recovery on reading progress, after adjusting for the effects of children's background characteristics. Note that to examine progress, you need to account for the pre-test measures of reading ability (or a combination of them). Pre-tests should also be included for the reason given in the study description above i.e. the non-random way in which children were assigned to either the control or the intervention group.

In your analysis, you should:

- Carry out appropriate descriptive analyses

- For regression analysis

Use a structured process to choose your final regression model
Check whether the assumptions of your model hold
Check for interaction effects

In your short report, you should:

- Justify all decisions made during your analysis, including how you selected your final model. This will include an analysis of how well your model fits and an appropriate analysis of the residuals.

- Give a full interpretation of your results.

- Include a short summary in which you describe your main conclusions without the use of statistical jargon.

- Include any clearly labelled tables and charts created from your SPSS output that you refer to in your report. (Additional supporting output can be included in an appendix.)

Question 2: As part of a survey of visual defects in partially sighted schoolchildren, two researchers asked 18 such children to read text at varying levels of luminance (Low, Medium, High). Six children at each of the three levels of partial sight ability (Poor, Average and Reasonable) were selected to participate in the experiment. Two children from each sight ability group were tested at one of the three levels of intensity of luminance. The data in the table below shows their reading performance scores. A higher performance score reflects a faster/more accurate reading speed.

Reading Performance Scores for 18 partially sighted school children by Sight Ability and Luminance Level

The data have been entered in SPSS. You will need to download the SPSS data file Sightlumin.sav from BLACKBOARD.

The Task

Carry out analysis using these data with the aim of discovering how differences in luminance levels and (partial) sight affect reading performance for these children.