Researchers were interested in comparing the long-term psychological effects of being on a high-carbohydrate, low-fat(LF) diet versus a high-fat, low-carbohydrate (LC) diet. A total of 106 over-weight and obese participants were randomly assigned to one of these energy-restricted diets. At 52 weeks, 32 LC dieters and 33 LF dieters remained. Mood was assessed using a total mood disturbance score (TMDS), where a lower score is associated with a less negative mood. A summary of these results follows:
This is the data table: http://prntscr.com/fynm9f
Is there a difference in the TMDS at week 52? Test the null hypothesis that the dieters’ average mood in the two groups is the same. Use significance level of 5%?
Critics of this study focus on the specific LC diet (that is, the science) and the dropout rate. Explain why the dropout rate is important to consider when drawing conclusions from this study.
This is the final question of my homework assignment and I am completely lost. Please help, state your work and formulas. Thank you. For part a, I have no idea. But for part b, drop out rate is important because 1. It may provide useful information. and 2.If dropout rate is too large, we have to use t-test since the remaining sample is too small. Otherwise we may use z-test.