Autism spectrum disorders are characterized by deficits in social functioning. Researchers were interested in better understanding how children with autism see and understand the world. Participants included children diagnosed with autism and typically developing children who were all approximately the same age. All children were presented with several different stimuli on a large computer screen for up to 1 minute. The stimuli were both social (i.e., people’s faces) and nonsocial (inanimate objects). The percentage of time children spent looking at the two types of stimuli were recorded (ranging from 0 to 100). The results are presented below:
DV: Time spent looking IV2: stimulus type
Social Nonsocial
IV1: diagnosis Autism 50 83
Typically Developing 80 50
1. Draw a line graph representing these results. Put diagnosis on the x-axis.
2. In the table below, compute the marginal means for each IV. Assume differences greater than 10 are statistically significant.
2a. Is there a main effect for IV1: diagnosis? If so, describe it.
DV: Time spent looking (remember, higher is slower) Variable 2: stimulus type
Social Nonsocial Main Effect for IV1:
Diagnosis. Compute Marginal Means
IV1: diagnosis Autism 50 83
Typically
Developing 80 50
Main Effect for IV2: Stimulus type Compute Marginal Means
2b. Is there a main effect for IV2: stimulus type? If so, describe it.
3. Now, in the table above, compute the difference of differences. Is there an interaction between stimulus type and diagnosis? If so, describe it.
