## Disease Detectives B/C

QuantumTech
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State: CA

### Re: Disease Detectives B/C

Lol I have so many questions but state is very soon. How do you guys put information about infectious diseases on your cheat sheet? I have the most common infectious diseases but I'm afraid of seeing a disease name on the test that I have never heard about. Wikipedia has a list of 216 infectious diseases but that seems like overkill... If I have to I can take out background info on the diseases and just place disease name/type and agent name.

yang573
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### Re: Disease Detectives B/C

Another question I have is for reading the stats table for z test... If the critical point we need is in between two numbers, like say 1.64 and 1.65, do we take the one nearest to the critical point or the average (1.645)?
If you look at the normal distribution function, it's a curve that does have a formula that can be found here: http://mathworld.wolfram.com/NormalDistribution.html. The curve means the slope of the function changes depending on the test statistic (which for the z-test, is $z$). So it's a little unpredictable to guess which value is closest (I suppose you could try using derivatives and such).

But using a TI system, the area under a curve can be returned using normCdf(low, high) - this would return the actual value of the probability of a value being in the selected part of the normal distribution. I doubt that a disease detectives test would use something that would not be on a "nice" value, i.e. 90%, 95%, or 99% levels. If they did not stick to such values, then they would likely provide the probability for the value that you will need. If you did end up getting this type of question on a test, I'd just use your judgement and make a "best guess" (although you might want to check to make sure you are computing the test statistic correctly).
I don't think you'll have to know the formula for a normal distribution function, especially if they give you a table with all the critical values. (Although that is good to know.)

Also, regarding the calculator, critical values are related to probability, but you need critical values, not probability for some calculations. That means you would need the invNorm function, not normCdf, in order to find critical values for those calculations. However, you can't use a programmable calculator on the test anyways, therefore you can't even use the aforementioned functions. If you need to calculate something using critical values, they should give you a table.
So much to do, so little time.

hmath729
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State: CA
Location: Helix Heights

### Re: Disease Detectives B/C

When using a line listing to graph an epi curve, do you use the time of onset (of symptoms) or the time of exposure? Had a little trouble with this at State, although we ended up using time of onset.
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dcrxcode
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Joined: March 22nd, 2015, 8:53 am
State: IN

### Re: Disease Detectives B/C

When using a line listing to graph an epi curve, do you use the time of onset (of symptoms) or the time of exposure? Had a little trouble with this at State, although we ended up using time of onset.
You're definitely right in using the time of onset because the epi curve is a graph of symptomatic onset in the population being studied.

JoJoKeKe
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Joined: April 27th, 2015, 6:29 pm
Division: C
State: ID

### Re: Disease Detectives B/C

I just had my state competition, and we will be advancing on to the national competition! I'm so excited!

However, the Disease Detective test was a little rough, and it was my worst event overall. I spent (approximately) one month in Green generation, so this was somewhat familiar, but they had Survivorship curve questions that I could not get correct to save my life. Have you ever encountered questions solely relating to population w/o the presence of disease detection? There was also a cell biology of agents part that we definitely failed...

My confidence in this event has definitely decreased. Any ideas on how to prepare for the above listed or anything of the like?

Tournaments (2016): State / Nationals
Fossils: 3 / 8
Disease: 7 / NA
Green Gen: NA / 37
Picture This: 1 / 17
Invasives: 1 / 24

Idaho State (2017):
Rocks - 2
Microbe 2
Ecology 3
Optics 4
Invasives: 1

Events 2019: Herpetology, Fossils, Dynamic Planet, Fermi Questions

yang573
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Posts: 35
Joined: April 1st, 2014, 12:25 pm
Division: C
State: NY
Location: Earth

### Re: Disease Detectives B/C

I spent (approximately) one month in Green generation, so this was somewhat familiar, but they had Survivorship curve questions that I could not get correct to save my life. Have you ever encountered questions solely relating to population w/o the presence of disease detection?
I've seen that on an Islip invy test, but that was about it for me.
There was also a cell biology of agents part that we definitely failed...
Interesting. Did it ask about the replication process of viruses or something? That doesn't sound like anything I've ever encountered.
So much to do, so little time.

dcrxcode
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Posts: 129
Joined: March 22nd, 2015, 8:53 am
State: IN

### Re: Disease Detectives B/C

There was also a cell biology of agents part that we definitely failed...
I got similar questions on my state test too - identify parts of a virus. Weirder still was the question that asked to identify parts of a microscope.

JoJoKeKe
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Posts: 101
Joined: April 27th, 2015, 6:29 pm
Division: C
State: ID

### Re: Disease Detectives B/C

I spent (approximately) one month in Green generation, so this was somewhat familiar, but they had Survivorship curve questions that I could not get correct to save my life. Have you ever encountered questions solely relating to population w/o the presence of disease detection?
I've seen that on an Islip invy test, but that was about it for me.
There was also a cell biology of agents part that we definitely failed...
Interesting. Did it ask about the replication process of viruses or something? That doesn't sound like anything I've ever encountered.
To your second question, no. I haven't really studied this at all so they might have been obvious questions, but they had things like: What agent has chitin as a recognizable feature? Which agent has segmented parts as an identifiable feature, etc.

Do you guys think I would have any use through adding some of this information to my cheat sheet?
Tournaments (2016): State / Nationals
Fossils: 3 / 8
Disease: 7 / NA
Green Gen: NA / 37
Picture This: 1 / 17
Invasives: 1 / 24

Idaho State (2017):
Rocks - 2
Microbe 2
Ecology 3
Optics 4
Invasives: 1

Events 2019: Herpetology, Fossils, Dynamic Planet, Fermi Questions

dcrxcode
Exalted Member
Posts: 129
Joined: March 22nd, 2015, 8:53 am
State: IN

### Re: Disease Detectives B/C

I spent (approximately) one month in Green generation, so this was somewhat familiar, but they had Survivorship curve questions that I could not get correct to save my life. Have you ever encountered questions solely relating to population w/o the presence of disease detection?
I've seen that on an Islip invy test, but that was about it for me.
There was also a cell biology of agents part that we definitely failed...
Interesting. Did it ask about the replication process of viruses or something? That doesn't sound like anything I've ever encountered.
To your second question, no. I haven't really studied this at all so they might have been obvious questions, but they had things like: What agent has chitin as a recognizable feature? Which agent has segmented parts as an identifiable feature, etc.

Do you guys think I would have any use through adding some of this information to my cheat sheet?
If you have room for it on your cheat sheet and can cover all of the other info, I don't see why it wouldn't help.

yang573
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Posts: 35
Joined: April 1st, 2014, 12:25 pm
Division: C
State: NY
Location: Earth

### Re: Disease Detectives B/C

To your second question, no. I haven't really studied this at all so they might have been obvious questions, but they had things like: What agent has chitin as a recognizable feature? Which agent has segmented parts as an identifiable feature, etc.

Do you guys think I would have any use through adding some of this information to my cheat sheet?
I'd probably add some of the basic and distinguishing characteristics of each agent to your reference sheet, if you don't have the time to memorize those features.

And in case you're wondering, fungi have chitin in their cell walls, and segmented parts could refer to parasites or chains of bacteria (although the separate "parts" are all individual bacterium).
So much to do, so little time.