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.