0.4. Psychologists wanted to investigate if smiling makes people feel happy. Participants were each shown a short video clip of a cartoon. Haifthe participants were asked to watch it whilst holding a pencil between their teeth, not touching their lips, so forcing them to smile. The other half were asked to watch it whilst holding the pencil just with their lips, not touching their teeth, which prevented them from smiling. Afterwards participants had to tell the psychologist how happy they felt on a scale of 1 [not very happy] to 10 {very happy}. i] Write a one tailed hypothesis for this study. {3} ii) Outline one strength and one weakness of using an independent measures design in this study. {5) iii) How could you make this study a matched pairs design? (3] iv} What is the independent variable {W} in this study and how has it been operationalized? [2} v) Explain how this research can be made externally valid and internally valid? (5) vi} What are the possible confounding and extraneous variables in the study? (3)