Question

using this scenario, health officials provided a questionnaire to participants to try and ascertain the cause of the illness. in the below table, fill in the attack rates in the table for the 3 foods. round to the nearest whole number. then indicate what food you think led to the outbreak.

	ate food	did not eat food
food items served	ill	not ill	total	attack rate	ill	not ill	total	attack rate
raw tuna	28	40	68	blank 1	12	120	132	blank 2
fruit salad	25	100	125	blank 3	15	60	75	blank 4
rice	31	110	141	blank 5	9	50	59	blank 6

the food that most likely led to the outbreak was blank 7.
blank 1 add your answer
blank 2 add your answer
blank 3 add your answer

Explanation:

Step1: Calculate attack rate for those who ate raw - tuna

The attack rate is calculated as $\frac{\text{Number of ill}}{\text{Total number who ate}} \times 100$. For those who ate raw - tuna, the number of ill is 28 and the total number who ate is 68. So the attack rate is $\frac{28}{68}\times100\approx41\%$.

Step2: Calculate attack rate for those who did not eat raw - tuna

For those who did not eat raw - tuna, the number of ill is 12 and the total number who did not eat is 132. So the attack rate is $\frac{12}{132}\times100\approx9\%$.

Step3: Calculate attack rate for those who ate fruit - salad

For those who ate fruit - salad, the number of ill is 25 and the total number who ate is 125. So the attack rate is $\frac{25}{125}\times100 = 20\%$.

Step4: Calculate attack rate for those who did not eat fruit - salad

For those who did not eat fruit - salad, the number of ill is 15 and the total number who did not eat is 75. So the attack rate is $\frac{15}{75}\times100 = 20\%$.

Step5: Calculate attack rate for those who ate rice

For those who ate rice, the number of ill is 31 and the total number who ate is 141. So the attack rate is $\frac{31}{141}\times100\approx22\%$.

Step6: Calculate attack rate for those who did not eat rice

For those who did not eat rice, the number of ill is 9 and the total number who did not eat is 59. So the attack rate is $\frac{9}{59}\times100\approx15\%$.

Step7: Determine the food that led to the outbreak

The food with the highest difference in attack rates between those who ate and those who did not eat is raw - tuna.

Answer:

Blank 1: 41
Blank 2: 9
Blank 3: 20
Blank 4: 20
Blank 5: 22
Blank 6: 15
Blank 7: Raw Tuna