IN-CLASS PROJECT CHAPTER 9 KEY
Use two decimals throughout for calculations and three for p values
The mean score for Scrabble players at the neighborhood center is = 215 points. The players read a book that claims it can raise scores significantly. After reading the book, a team of n = 36 players obtains a score of M = 220 points, with s= 25. Do the data indicate that reading the book leads to increases in the players’ scores? Test with = .01.
Formulate the hypotheses.
Determine the critical value(s).
Calculate the test statistic.
Calculate and evaluate Cohen’s d and r2.
What decision can you make and what does it indicate?
What type of error could you be making?
Report your results with an APA-style phrase.
The Flynn effect indicates that IQ increases regularly in the population year by year. To test the effect researchers used a 20-year-old IQ test to a group of n = 49 20-year-olds. The average score of the sample was 107 with s = 12. Test with = .05.
Formulate the hypotheses.
Determine the critical value(s).
Calculate the test statistic.
Calculate and evaluate Cohen’s d and r2.
What decision can you make and what does it indicate?
What type of error could you be making?
Report your results with an APA-style phrase.
