Convert the following table extracted from the Gordis text:
TABLE 2-5. Food-Specific Attack Rates for Items Consumed August 16, 1974, Dade
County Jail, Miami
ATE
DID NOT EAT
Item Consumed
Sick Total % Sick (Attack Rate) Sick Total % Sick (Attack Rate)
P
Beverage
179
264
67.8
22
50
44.0
<.010
Egg salad sandwiches
176
226
77.9
27
73
37.0
<.001
From Centers for Disease Control and Prevention: Outbreak of foodborne streptococcal disease. MMWR 23:365, 1974.
Into a 2x2 contingency table, as seen in class, for the contaminated food to test the
hypothesis that there is no difference between the rate/proportion of sickness among
those that ate the Egg salad sandwiches and those that did not.
Complete the necessary steps for this two-sided hypothesis test, including
i. Defining the appropriate alternative hypothesis: Ha and null hypothesis: Ho
ii. Calculate the p-value and determine if there is sufficient evidence to reject the
null hypothesis.
Recall, the p-value for a two-sided test requires is doubling the p-value had
we did a one-sided test, i.e. 2. P(Z > Zcat]).
iii. Drawing a conclusion based on the results observed