Results for writing tut

Participants

There were 382 students who contributed to the data set; N = 185 in group 1 and N = 197 in group 2.

Method

Group 1 were told that Baby A was preterm and Baby B was full term. Group 2 were told that Baby A was full term and Baby B was preterm.

Participants in both groups rated each infant on 4 tasks

• fine motor
• gross motor
• self help
• play

Individual task ratings were averaged to produce a mean rating score for each skill, for each infant.

Research question

Does knowing preterm status bias experimenters judgements about locomotor status?

• Will Group 1 rate Baby A less competent than Group 2?
• Will Group 2 rate Baby B less competent than Group 1?

Plots

Fine and gross motor behaviour

Self help and play behaviour

Statistics

Hypothesis 1

Averaged across task, Group 1 will rate Baby A less competent than Group 2?

Is there a significant group difference in the Baby B ratings?

## 
##  INDEPENDENT SAMPLES T-TEST
## 
##  Independent Samples T-Test                                                                   
##  -------------------------------------------------------------------------------------------- 
##                             Statistic    df          p                          Effect Size   
##  -------------------------------------------------------------------------------------------- 
##    rating    Student's t    -11.23097    1501.000    < .0000001    Cohen's d     -0.5796458   
##  --------------------------------------------------------------------------------------------

Hypothesis 2

Averaged across task, Group 2 will rate Baby B less compentent than Group 1

Is there a significant group difference in the Baby B ratings?

## 
##  INDEPENDENT SAMPLES T-TEST
## 
##  Independent Samples T-Test                                                                  
##  ------------------------------------------------------------------------------------------- 
##                             Statistic    df          p                         Effect Size   
##  ------------------------------------------------------------------------------------------- 
##    rating    Student's t     2.047690    1492.000    0.0407651    Cohen's d      0.1059963   
##  -------------------------------------------------------------------------------------------