Chicken Consumption and Sickness in Teenagers, Case Study Example

The type of study to be used is a case control study. Though it is suspected that the sickness is due to consuming chicken, the exact origin should be determined in order to prevent further outbreaks. If chicken did not cause the sickness, then other factors can be investigated.

An odds ratio will be used to determine the probability that the teenagers became sick from eating the chicken. A chi squared test will be used to determine the probability that the teenagers becoming sick had no relationship to chicken consumption.

The odds ratio of students getting sick from eating the chicken is 2.333. Because the odds ratio is greater than 1, the there is a high chance that the teenagers who ate the chicken would become sick. The 95% confidence interval is used to estimate the precision of the odds ratio and is 0.5874 to 9.2683. Because it contains 1.0, the association is not statistically significant at the 0.05 level.

The odds ratio is calculated: (35/5)/(15/5) = 2.333

The 95% confidence interval is calculated:

e^[ln(2.333) + 1.96*SE(1/35 + 1/15 + 1/5 +1/5) =  9.2683

e^[ln(2.333) – 1.96*SE(1/35 + 1/15 + 1/5 +1/5) = 0.5874

SE = square root.

The null hypothesis for the chi squared test is that consumption of the chicken is not associated with the teenagers becoming sick. The alternative hypothesis is that the consumption of the chicken caused the teenagers to become sick. The degree of freedom is 1 and the predetermined alpha level of significance is 0.05. The p-value is 0.221 and greater than the alpha level of significance. Because the chi squared is less than the critical value for the 0.05 probability level of 3.841, the null hypothesis is accepted. The chi squared is calculated:

x² = [(35*5 – 15*5)²*(35+15+5+5)] /[(35+15)*(5+5)*(35+5)] = 1.5000

Relationship of Sickness and Consumption of Chicken in Teenager

Though the odds ratio indicates that there is a high probability that the chicken caused the teenagers to become sick, the 95% confidence interval indicate that this is an unreliable estimate. The chi squared test indicates that the consumption of the chicken has no relationship to the teenagers becoming sick.