8. Investigators collect data from a case-control study investigating the asso- ciation between infant mortality and breast feeding. Cases were children who died during infancy (first year of life) while controls were children who survived until at least one year of age. Infants were classified into one of three exposure categories: i. exclusive breast-feeding; ii. breast milk + other milk + non-milk supplement; ii. non-breast milk only. (a) Exposure is measured on an ordinal scale. (b) A statistically significant test statistic implies that breast feeding and infant mortality are independent at the population level. (c) Degrees of freedom for the chi-square test depends on sample size. (d) Test validity is assured if there are at least five observations in each cell of the contingency table. 8. Investigators collect data from a case-control study investigating the asso- ciation between infant mortality and breast feeding. Cases were children who died during infancy (first year of life) while controls were children who survived until at least one year of age. Infants were classified into one of three exposure categories: i. exclusive breast-feeding; ii. breast milk + other milk + non-milk supplement; ii. non-breast milk only. (a) Exposure is measured on an ordinal scale. (b) A statistically significant test statistic implies that breast feeding and infant mortality are independent at the population level. (c) Degrees of freedom for the chi-square test depends on sample size. (d) Test validity is assured if there are at least five observations in each cell of the contingency table