In a planned study, there is a known population with a normal distribution, = 55, and o = 4. What is the predicted effect size if the researchers predict that those given an experimental treatment have a mean of (a) 55, (b) 56, (c) 59, (d) 61, and (e) 47? For each part, also indicate whether the effect is approximately small, medium, or large. (a) d= (Type an integer or decimal rounded to three decimal places as needed.)