Disease Detectives B/C Question Marathon

[CaRoLyN_s]

Here are my tries:

Outbreak vs. Epidemic vs. Pandemic: (Click to Show Hidden Text)

Outbreak: occurrence of more cases of a health condition than usual in a given area. Epidemic: a widely dispersed, rapidly spreading occurrence of disease in an area. Pandemic: an epidemic on a global scale.

You're correct, continue!
Let's keep this marathon alive!

[nomynameisnotkevin]

Ok, so I encountered a question regarding immunity for a certain illness (stomach flu/gastroenteritis).
So without further adieu, maybe someone can help out with this question.
Is Immunity generally lifelong (I assume for this illness, the question isn't clear).? (True/False, and why)

Here's an extra question in case the first question is terrible:
If there is a epi-curve that is stratified (stacked segments of bars for different age groups), is the peak where there's the highest number of any group? or is the peak at where the highest aggregate bar (add up all the sections and see which one stacks the highest)?

[CulturallyScientific]

Next question for the marathon!

The National Health Interview Survey reported the percent of respondents with a hearing problem by age group during 2005. Would it be correct to state that the risk of hearing loss increases with age? Be sure to explain and defend your answer.

DATA:
8.2% of 18-44 year-olds reported a hearing problem.
19.2% of 45-64 year-olds reported a hearing problem.
30.4% of 65-74 year-olds reported a hearing problem.
48.1% of 75+ year-olds reported a hearing problem.

[nomynameisnotkevin]

I can see this going two ways:

1. Yes, this can be assumed, as much more people that are older (higher percent) have such an issue.

My AP Stats background tells me:

2. NO! First of all, we don't know if it is a ramdom sample, so we don't know if we can apply it to the population. In addition, what constitutes as a hearing problem? Third of all, the syntax of risk of hearing loss increases with age is poor, as it's not necessary that the risk goes up to cause these #s. For example, there are more young people that are healthy than old people. So not everyone lives to an age beyond 75. Those who do may often encounter degenerative diseases simply for living longer, not that the risk of hearing loss increases with age, but that you have longer to develop a problem, if that makes sense.

[CulturallyScientific]

I can see this going two ways:

1. Yes, this can be assumed, as much more people that are older (higher percent) have such an issue.

My AP Stats background tells me:

2. NO! First of all, we don't know if it is a ramdom sample, so we don't know if we can apply it to the population. In addition, what constitutes as a hearing problem? Third of all, the syntax of risk of hearing loss increases with age is poor, as it's not necessary that the risk goes up to cause these #s. For example, there are more young people that are healthy than old people. So not everyone lives to an age beyond 75. Those who do may often encounter degenerative diseases simply for living longer, not that the risk of hearing loss increases with age, but that you have longer to develop a problem, if that makes sense.

In response to your answers:
1. Incorrect... the reasoning is not correct.
2. Yes, it is a random sample, with equal numbers of randomly sampled people per age group. A hearing problem is simply what it says - a medical condition/issue with hearing.
I won't really comment on the rest of your reasoning for the rest of your 2nd point, since you don't use it to support your response to the original question: whether or not it would be correct to state the risk of hearing loss increases with age, based on the data given.

[Crazy Puny Man]

Next question for the marathon!

The National Health Interview Survey reported the percent of respondents with a hearing problem by age group during 2005. Would it be correct to state that the risk of hearing loss increases with age? Be sure to explain and defend your answer.

DATA:
8.2% of 18-44 year-olds reported a hearing problem.
19.2% of 45-64 year-olds reported a hearing problem.
30.4% of 65-74 year-olds reported a hearing problem.
48.1% of 75+ year-olds reported a hearing problem.

It sounds to me like the answer is yes...but I don't know how to defend it. Are you looking for a statistical test to demonstrate that there is a significance? (warmer?)

[CulturallyScientific]

It sounds to me like the answer is yes...but I don't know how to defend it. Are you looking for a statistical test to demonstrate that there is a significance? (warmer?)

Unfortunately, cooler.
I'll post the answer within 24 hours if no one can guess correctly, just for the sake of the marathon to keep going!
And my apologies if this is a bad question.

[Flavorflav]

Next question for the marathon!

The National Health Interview Survey reported the percent of respondents with a hearing problem by age group during 2005. Would it be correct to state that the risk of hearing loss increases with age? Be sure to explain and defend your answer.

DATA:
8.2% of 18-44 year-olds reported a hearing problem.
19.2% of 45-64 year-olds reported a hearing problem.
30.4% of 65-74 year-olds reported a hearing problem.
48.1% of 75+ year-olds reported a hearing problem.

I assume you're going for an incidence v. prevalence problem - since the hearing issue is likely to persist for the rest of your life, number of cases is less relevant to risk than # of new cases. However, it looks like the data still supports an increase in incidence. You would really need the age breakdown so you could calculate person-years and I'm too lazy to look that up. Without adjusting for population it looks like you have roughly 0.3%/year in the youngest group (although this is inflated, since we don't have data on people under 18), about 1%/year for the next, and 3% a year for the next group. The oldest group can't be estimated this way since the upper limit is death, but I'd be willing to bet that after age-adjustment it works out to a pretty high rate of new cases.

[CulturallyScientific]

Next question for the marathon!

The National Health Interview Survey reported the percent of respondents with a hearing problem by age group during 2005. Would it be correct to state that the risk of hearing loss increases with age? Be sure to explain and defend your answer.

DATA:
8.2% of 18-44 year-olds reported a hearing problem.
19.2% of 45-64 year-olds reported a hearing problem.
30.4% of 65-74 year-olds reported a hearing problem.
48.1% of 75+ year-olds reported a hearing problem.

I assume you're going for an incidence v. prevalence problem - since the hearing issue is likely to persist for the rest of your life, number of cases is less relevant to risk than # of new cases. However, it looks like the data still supports an increase in incidence. You would really need the age breakdown so you could calculate person-years and I'm too lazy to look that up. Without adjusting for population it looks like you have roughly 0.3%/year in the youngest group (although this is inflated, since we don't have data on people under 18), about 1%/year for the next, and 3% a year for the next group. The oldest group can't be estimated this way since the upper limit is death, but I'd be willing to bet that after age-adjustment it works out to a pretty high rate of new cases.

This is more or less what I was going for, yes. The answer I had in mind is that since the data given is all prevalence data, conclusions can't be drawn about risk because risk can only be calculated from incidence.
Your turn!

[nomynameisnotkevin]

Sorry, totally misread that question. I see what you mean by the data now. Read your data as incidence instead...