Mathematics Scores Worldwide. The National Center for Educational Statistics publishes the results from the Trends in International Math and Science Study (TIMSS). The table contains the 2007 and 2011 mean mathematics scores for eighth-graders from various countries. Assume that the population of score differences is normally distributed. Use this information for Exercises 39–44.
| Country | 2007 | 2011 |
|---|---|---|
| Singapore | 593 | 611 |
| Japan | 570 | 570 |
| Hong Kong | 572 | 586 |
| England | 513 | 507 |
| United States | 508 | 509 |
| Hungary | 517 | 505 |
| Italy | 480 | 498 |
| Russia | 512 | 539 |
| Ukraine | 462 | 479 |
| Australia | 496 | 505 |
| South Korea | 597 | 613 |
| Slovenia | 501 | 505 |
| Thailand | 441 | 427 |
| Norway | 469 | 475 |
| Indonesia | 397 | 386 |
mathscores
39. Explain why these are dependent samples and not independent samples.
10.1.39
The mean mathematics score in 2007 and 2011 are given for the same country for each of the 15 different countries.