# Binomial probability calculation tool for food exposures

(Excel format, 10 sheets, 476KB)

HOW THIS TOOL WORKS:

This Excel document calculates binomial probabilities using Foodbook 1 and Foodbook 2.0 values as a reference population and flags exposures of interest (alert) for further follow-up. There are over 300 pre-filled food items with the ability to add more items as needed. When adding additional exposures, do not insert rows. Simply add them to the bottom of the current list in order to maintain formulas and formatting.

When possible, values from Foodbook 2.0 are presented and replace the data from Foodbook 1. However, if the variable was included in Foodbook 1 only, it is presented here, marked in the table with an *

HOW TO USE THIS TOOL:

Tool A
Select your province/territory of interest in cell P1. Enter the total number of cases that reported Yes (Y), Probably (P), No (N) or Don’t Know (DK) to each of the food exposures listed and the tool will do everything else! The formulas used in Tool A for each calculated cell are as follows:

• Column J calculates the percentage of cases who reported Yes (Y) and Probably (P) by dividing the sum of column C (Yes) and column D (Probably) by the sum of columns C (Yes), D (Probably), and E (No), and multiplying it my 100 to obtain a percentage.
• Column G calculates the sum of column C (Yes) and column D (Probably)
• Column H calculates the sum of  columns C (Yes), D (Probably), and E (No)
• Column K is the data from the Public Health Agency of Canada’s Foodbook 2.0 study.
• Column L calculates the binomial probability of each food item using the reference data.
• Column M determines whether each exposure of interest is significant: if the p-value is less than, or equal to 0.05 AND the proportion of individuals who reported consuming a food item is greater than the Reference, OR, if no reference value exists, then if the value is greater than or equal to 60%

Tool B
Enter your variable names and values for “Yes”, “Probably”, “No” and “Don’t know” into the sheet “Values-Valeurs”. Ensure that all of your variable names and labels are included in the “Variables” sheet. If the variable is not in Foodbook, then make sure that the value in Column B is equal to “381”.

TO NOTE:

• The characters “#DIV/0!” appear in the table below when a number is divided by zero (0). It happens when you enter a formula like =21/0, or when a formula refers to a cell that has 0 or is blank.

Exposures of Interest are:

• those with p-values ≤ 0.05 and where the observed proportion is greater than the expected (reference) population [i.e. %Y+P > %Reference],
• OR, if there is no expected or reference value, then when the observed proportion (%Y+P) is greater than or equal to 60%

## Control Data Reference:

BINOMIAL PROBABILITY CALCULATION TABLE: