| Date | November 2011 | Marks available | 2 | Reference code | 11N.3.SL.TZ0.1 |
| Level | Standard level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Compare | Question number | 1 | Adapted from | N/A |
Question
Within a cross-sectional study “Fit for Life” in Germany, the body mass index (BMI) of volunteers aged between 16 and 25 years was investigated. Volunteers were also interviewed about their daily exercise habits. The graphs below show the percentage of men and women who were overweight, and the percentage who exercised daily.
Measure the difference between the percentage of overweight men and the percentage of overweight women at age 20.
State the range of the body mass index (BMI) that corresponds to overweight status.
Compare the percentage of men and women who exercised daily.
Evaluate the hypothesis that being overweight is due to lack of exercise.
Markscheme
10 (%) (allow responses in the range of 9 to 11 %)
25.0 −29.9 / above 25 and below 30
Do not accept 30 as this is classed as obese.
more women exercise than men;
both show an increase (between ages 16 to 25);
similar trend lines over time / slightly greater increase in women;
women have greater increases and decreases/greater variability while men gradually increase/stays level;
Award any one of the above marking points if shown as a valid numerical comparison.
(hypothesis is supported) as the greater percentage of men are overweight and they exercise less than women / vice versa;
(hypothesis is supported) lowest percentages of overweight ages (18 and 20) correspond with peaks of exercise;
(hypothesis is not supported) as even though both men and women exercise more over time the percentage overweight also increases;
(hypothesis is not supported) other named factor which influences being overweight; (e.g. availability of cheap high energy foods / large portion sizes / increasing use of vehicles for transport / changes from active to sedentary occupations / genetics)
BMI does not consider muscle mass/bone structure/bone density;
only narrow range of ages considered;
Examiners report
Almost all candidates read the graphs correctly to obtain the correct difference between overweight men and women.
Many did not give the correct range for the BMI corresponding to overweight status, giving incorrect upper limits.
Many candidates were able to get one mark for indicating that more women exercise than men but only some were able to get a second mark.
Candidates struggled with this question, primarily as they did not use the data to evaluate the hypothesis given. Instead of looking at how the data either supports or does not support the hypothesis, they talked in general about factors that could influence being overweight. One comment on the G2 forms indicated that it was hard to find 3 points for an answer to this when in fact the mark scheme provided 6 ways of getting the points.
