a book of critical thinking activities for students

The argument in the following exercise looks fairly straightforward at first blush, but statistical data should always be treated with caution. Try to analyse the argument in terms of its claim and premises. Does all the information add up to the conclusion, or is there reason to think the conclusion should be doubted?



Exercise 7.1

Living in the US makes you fat.* A team at Northwestern University in Chicago investigated whether there were changes in the waistlines of immigrants, most of whom come from countries with lower rates of obesity than the US, after moving to one of the world’s fattest countries. The team pulled data from the 2000 National Health Interview Survey, which is based on detailed interviews with 32,374 adult US residents. The Northwestern team found that after a year or less in the US, only 8 per cent of immigrants were obese. But after 15 years of American life, the figure rose to 19 percent – approaching the 22 per cent of US-born survey respondents who were obese. The 15-year link with obesity held for immigrant whites, Latinos and Asians, but not for foreign-born blacks. Significant weight gain did not appear until immigrants had lived in the US for at least 10 years. The team says this threshold may reflect how long it takes new residents to adopt the high-calorie diet and sedentary lifestyle that can make US-born Americans so large.

Type of argument: _________________________________________
Claim: _________________________________________________________

It is a good / bad argument because __________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________

*This text has been adapted for non-commercial, educational purposes from here.

When you are ready, check out the answer here, or continue reading…