Mean differences between an experimental and control group

1) Answer questions below:

                       a) A researcher makes a prediction regarding the direction of mean differences between an experimental and control group. When deciding on a sample size should s(he) use a ‘one’ or ‘two’ tailed test in her decision? ___________

b) When raw scores are converted to standard scores, the resulting distribution has a mean equal to ________and a standard deviation equal to what_______?

c) The null hypothesis assumes there is no relationship between variables. (True/ False)

d) When a researcher rejects the ‘null hypothesis’ it means there are statistically significant results indicating a relationship between the variables. (True/ False)=

2) A young man’s score on an anxiety scale is 31. The population mean score is 27.3 and s.d. is 10.2. Find his ‘z’ score and report his corresponding percentile rank. Use Kim & Mallory pps. 121-125 for guidance.