1. A cross-sectional study is conducted on a range of health problems among men and women aged 80 and above living in a nursing home.

	Malnourished	Well-nourished	Total
Men	18	66	84
Women	93	145	238
Total	111	211	322

	Diabetes	Not diabetes	Total
Men	7	77	84
Women	18	220	238
Total	25	297	322

1. Based on the information in the tables above, what is the prevalence of malnutrition among men and women in this age group?

1. Based on the information in the tables above, what is the prevalence of diabetes among men and women in this age group?

1. You have conducted a cross-sectional study on anemia (defined as hemoglobin level of less than the 5th percentile for age) among primary school children in 5 randomly selected schools.

	Girls	Boys	Total
Anemia	431	323	754
Not anemia	2014	2672	4686

1. What is the prevalence of anemia among girls and among boys and overall?

1. What is the OR of having anemia for girls compared to boys?
2. What is the prevalence ratio of having anemia for girls compared to boys?

1. A survey has been conducted on the use of illegal drugs among secondary school pupils. Below is a table on the number of participants who smoke and use illegal drugs.

	Smokes	Does not smoke	Total
Uses illegal drugs	67	34	101
Does not use illegal drugs	786	845	1631

1. What is the prevalence of illegal drug use among smokers and non-smokers and overall?
2. What is the OR of using drugs for smokers compared to non-smokers?

1. What is the prevalence ratio of using drugs for smokers compared to non-smokers?

1. In the study mentioned in exercise 1, the proportion with hypertension is calculated to be 0.145 with a 95% confidence interval from 0.11 to 0.17. Explain what how we should interpret the confidence interval.

1. A hypothetical cross-sectional study to determine the prevalence of stunting in different age groups of children below age 6, finds the following distribution.

Age	<2 years	2-3 years	4-5 years	Total
Stunted	93	78	43	214
Not stunted	107	111	175	393
Total	200	189	218	607

1. What is the prevalence of stunting in each of the age groups and overall?
2. What is the OR of stunting among those aged <2 years compared to those aged 4-5 years?
3. What is the prevalence ratio of stunting among those aged <2 years compared to those aged 4-5 years?