1. Describe what a scatter diagram would look like for each of the following situations:
a. a perfect correlation,
b. a weak positive linear correlation, and c. no correlation.
2. Researchers Sync and Smith reported a significant correlation between children's reading level and intelligence measured as an IQ score (r=.23). The same researches reported that the correlation between math ability and knowledge of social studies was not significant (r=.15). Explain these results as if you were writing to a person who has never had a course in statistics. Be sure to discuss
a. significance,
b. the direction and strength of the relationship,
c. causality, and
d. r2 where applicable. (for a total of 9 marks)
3. A researcher studying adjustment to the job of new employees found a correlation of .30 between amount of employees' education and rating by job supervisors two months later. The research now plans to use amount of education to predict supervisors' later ratings of employees. Indicate the
a. predictor variable,
b. criterion variable, and
c. the standardized regression coefficient (?).
d. Write the Z score prediction model.
Given the predicted Z scores of 1. -1.5. 2. -1. 3. -.5 4. 0, and 5. +.5.