# Public health calculation | Science homework help

1. An epidemiologist wants to know the incidence of a new respiratory disease in Antigua, Guatemala over the month of January. The population of Antigua is 47,000. At the start of the month, 300 people have the disease. 700 have already had it and are immune. What is the total population at risk for the month?

2. Age Adjustment Scenario: You are a public data health analyst for the Ministry of Health in Guatemala. You and your colleagues are concerned with the increasing number of a new respiratory disease cases emerging in Antigua among children ages 1-15. You decide to look more into the incidence of the disease for the period of January 2022 to February 2022. Use the following information to calculate the age-adjusted incidence rate for respiratory disease cases in Antigua, considering the age distribution of Guatemala. Write the age-adjusted incidence rate as the number of cases per 1,000 people.

Between January 2022 to February 2022, there were 2,000 respiratory disease cases among children aged 1-15 in Antigua.

During this time period, there were 1,100 respiratory disease cases among all other age groups

Antigua population at risk = Answer from previous question

Age distribution for Antigua and Guatemala are as follows:

1-15 year olds: 25% of the Antigua population vs. 15% of the Guatemala population

All others age groups: 75% of Antigua population vs. 85% of Guatemala population

3. For the next four questions, use the following information:

A researcher believes that bacteria in fast food is causing diarrheal illness. She decides to do a case-control study. She recruits the 80 people who had diarrhea in October and 80 control subjects. Of the 80 cases, 41 reported that they had fast good in October. Of the 80 controls, 9 reported that they had fast food in October.

Ideally, what types of people should she try to recruit as control subjects?

a. Individuals who have the same characteristics as the cases in every possible way.

b. Individuals who have the same characteristics as the cases (except for the exposure of interest).

c. Individuals who have the same characteristics as the cases (except for the disease of interest).

4. A researcher believes that bacteria in fast food is causing diarrheal illness. She decides to do a case-control study. She recruits the 80 people who had diarrhea in October and 80 control subjects. Of the 80 cases, 41 reported that they had fast good in October. Of the 80 controls, 9 reported that they had fast food in October.

In a 2×2 table setting up this problem to calculate the odds ratio, the number in Cell A would be:

5. A researcher believes that bacteria in fast food is causing diarrheal illness. She decides to do a case-control study. She recruits the 80 people who had diarrhea in October and 80 control subjects. Of the 80 cases, 41 reported that they had fast good in October. Of the 80 controls, 9 reported that they had fast food in October.

What is the odds ratio for having diarrhea among those who ate fast food in January? Carry out your answer to 2 decimal places.

6. A researcher believes that bacteria in fast food is causing diarrheal illness. She decides to do a case-control study. She recruits the 80 people who had diarrhea in October and 80 control subjects. Of the 80 cases, 41 reported that they had fast good in October. Of the 80 controls, 9 reported that they had fast food in October.

Assuming the odds ratio you found above is statistically significant, what do you conclude from this odds ratio?

a. Those who ate fast food in October are XXX times more likely to have diarrhea than those who did not eat fast food in October.

b. Those who have diarrhea are XXX times more likely to have eaten fast food in October than those who do not have diarrhea.

c. Those who ate fast food in October are XXX times more likely to have diarrhea.

d. Those who ate fast food in October are XXX times more likely to have diarrhea than those who did not have diarrhea.

7. For the next two questions, assume the following:

There are 2,000 people on a cruise ship.

There is an epidemic of a disease known as Vacation Doozy that is sweeping through the ship.

Once you’ve gotten Vacation Doozy and recovered, you are immune to it forever.

400 people on the ship have previously had Vacation Doozy.

600 people on the ship were previously vaccinated against Vacation Doozy, so they are immune forever.

There were 10 people with existing cases of Vacation Doozy on June 1.

There were 80 new cases of Vacation Doozy from June 1 to June 30.

The total population on the ship at risk for Vacation Doozy in the month of June is:

8. There are 2,000 people on a cruise ship.

There is an epidemic of a disease known as Vacation Doozy that is sweeping through the ship.

Once you’ve gotten Vacation Doozy and recovered, you are immune to it forever.

400 people on the ship have previously had Vacation Doozy.

600 people on the ship were previously vaccinated against Vacation Doozy, so they are immune forever.

There were 10 people with existing cases of Vacation Doozy on June 1.

There were 80 new cases of Vacation Doozy from June 1 to June 30.

What was the incidence rate of Vacation Doozy on the ship from June 1 to June 30? Carry out your answer to 2 decimal places.

9. For the next two questions, use the following information:

In a study of the effect of drinking alcohol daily on cognitive decline, a scientist recruits and follows 600 people for 30 years. The study began in 1992 and today the scientist finds:

205 people drank alcohol daily. Of these 205 people, 99 experienced cognitive decline.

Of those who did not drink daily, 77 experienced cognitive decline.

What is the relative risk of experiencing cognitive decline among people who drink daily? Carry out your answer to 2 decimal places.

10. In a study of the effect of drinking alcohol daily on cognitive decline, a scientist recruits and follows 600 people for 30 years. The study began in 1992 and today the scientist finds:

205 people drank alcohol daily. Of these 205 people, 99 experienced cognitive decline.

Of those who did not drink daily, 77 experienced cognitive decline.

How would you interpret your relative risk finding?