The "Reading the Mind in the Eyes Test" (RMET) measures the ability of a person to infer the mental state of another from looking at facial expressions. Researchers Domes et al. (Biological Psychiatry, 2007) conducted a study on the effect of oxytocin (a hormone often linked with bonding, trust, and empathy) on people's performance on the RMET.30

healthy male volunteers (ages 21-30 years) were administered oxytocin and a placeboeach as a nasal spray, in a random order and with a week of washout period between the two treatments. Forty-five minutes after administering each treatment, participants were given the RMET. The researchers noted that the average increase in RMET score when on oxytocin compared to when on the placebo was3

points, with a standard deviation of6.97

points. The differences in RMET scores were not strongly skewed.

1. Define the appropriate parameter(s) of interest in the context of the study. Also, state the appropriate symbol(s) to denote the parameter(s).

1. State, using the symbol(s) described in part (a), the appropriate null and alternative hypotheses to test whether the use of oxytocin causes an increase in ability to infer the mental state of others, as measured by the RMET score.

1. Regardless of your answer to part (c), perform a theory-based test to test the hypotheses stated in part (b). Report a test statistic value and a p-value in your answer.Round the test statistic to 2 decimal places, e.g. 5.83, and the p-value to 4 decimal places, e.g. 0.0583.

t= , p-value =