In 1987 sinusitis was the most common chronic medical condition in the

One important point you need to understand to understand this question is the increase in average age of a population.
Lets say average age of US population is 40 yrs. (Add ages of all people and divide by the number of people). The average age need not increase with time (it can even reduce e.g. when life expectancy decreases; people live shorter lives; lots of new babies are born) If average age increases to 50 yrs, it means people are living longer lives or not many new babies are being born or both (a problem being faced by much of the developed world today)
So when we say average life increased, it is probably because there are more aged people.

Premises:
- In 1987 sinusitis most common chronic condition followed by arthritis and high blood pressure
- More arthritis and high blood pressure with age
- Incidence of sinusitis is the same for people of all ages
- Average age will increase between 1987 and 2000.

Let's refresh what we said about conclusion questions - should be implied from the argument and should give no new data.

(A) Sinusitis will be more common than either arthritis or high blood pressure in 2000.
With increase in average age, we cannot say this. It is possible that other two become more common.

(B) Arthritis will be the most common chronic medical condition in 2000.
Definitely no reason to pick Arthritis out of the two - BP and Arthritis so no need to even think about it.

(C) The average age of people suffering from sinusitis will increase between 1987 and 2000.
Since incidence of sinusitis is the same for all ages, we can conclude that the average age of a person suffering from Sinusitis is the same as the average age of the population. Since average age of population will increase, average age of people suffering from Sinusitis will also increase.

(D) Fewer people will suffer from sinusitis in 2000 than suffered from it in 1987.
Sinusitis does not depend on age so cannot be concluded.

(E) A majority of the population will suffer from at least one of the medical conditions mentioned above by the year 2000.
No reason to conclude this.

No. We do not know the current incidence of sinusitis, arthritis and high BP. The 'average age increases' implies either people live longer than before or no. of people who are aged are more than before or both, but it doesn't imply that majority of people are aged. 'Majority' means more than half. We have no data to conclude that more than half people will be aged. We also have no data to conclude that majority of people will have one of the given diseases e.g.

Sinusitis incidence - 10 in 100 people
Arthritis - 3 in 100 aged people
High BP - 2 in 100 aged people
When the population becomes more aged:
e.g. Sinusitis incidence - 10 in 100
Arthritis - 5 in 100 aged people
High BP - 3 in 100 aged people

Not every one who is aged, has to have one of these diseases.

(C) it is.

(A) Sinusitis will be more common than either arthritis or high blood pressure in 2000. -- One never knows suddenly people start eating too much of salt and have high blood pressure. So this cant be concluded

(B) Arthritis will be the most common chronic medical condition in 2000. -- again with the same reason given for (A).

(C) The average age of people suffering from sinusitis will increase between 1987 and2000 -- Yeah this can be safely concluded provided all suffering from sinusitis do not die.

(D). Fewer people will suffer from sinusitis in 2000 than suffered from it in 1987{#} --- Sounds weird.

(E) A majority of the population will suffer from at least one of the medical conditionsmentioned above by the year 2000. -- Cant be concluded.

I vote for C since it is more logical than any other choices.
Between 87 to 2000 ppl having sinus will grow and their average age will also increase.
IMO C

Karishma You said there are more aged people.
So the majority of the population is aged and the incidence of arthritis and high BP increases with age.Isnt this enough to conclude that A majority of the population will suffer from at least one of the medical conditions mentioned above by the year 2000.
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not enough reason to choose C
the incidence rate is same for sinoc at all ages
It DOES NOT mean it avg age of people suff from sinoc WILL INCREASE !
lets check, 100 people of different ages, all have same probability to catch sinoc (it does not mean ALL OF THEM will get sinoc for sure). What if only one person aged 20 yrs is infected with sinoc and others are okay ? Will it SURELY INCREASE the avg age of people attacked with sinoc (option C) ???

"the incidence rate for sinusitis is the same for people of all ages." implies that the % of people who get it will be the same in all age ranges.
So if 1% of 20 yr olds get it, only 1% of 30 year olds will get it and only 1% of 3 yr olds will get it. So people who get sinusitis are a small but proportionate sample of the entire population. Since the representation of each age group is the same as in the actual population,

Average age of people with sinusitis = Average age of the population.

If average age of the population goes up, the average age of people with sinusitis will go up.

C is the correct answer

A) Sinusitis will be more common than either arthritis or high blood pressure in 2000. >> Can't say this from given info

(B) Arthritis will be the most common chronic medical condition in 2000. >> Can't say this from given info

(C) The average age of people suffering from sinusitis will increase between 1987 and 2000. >> Note that passage says, average age of population will increase between 1987 - 2000. Passage also says that rate for sinusitis is the same for people of all ages. Additing these two data pointers, we can conclude C

(D) Fewer people will suffer from sinusitis in 2000 than suffered from it in 1987. >> Can't say this from given info

(E) A majority of the population will suffer from at least one of the medical conditions mentioned above by the year 2000. >> Too general

Hi

Why cannot A be the answer?

My explanation for A:
The passage says The incidence rates for both arthritis and high blood pressure increase with age.....The average age of the United States population will increase between 1987 and 2000.
if the average age is expected to increase and we know that incidence rate for arthritis and high BP increase with age, we can say that incident rate for these two problems has reduced => Sinusitis will be more common.

Check the question stem once again -



1. Sinusitis {Remains same with age }
2. Arthritis {Increases with age}
3. Blood Sugar {Increases with age}

Further it is given



Consider simple numbers for the same

Let there be 2 people , age of the 2 people be 10 and 30

Average age of the 2 people in year 1 is = 20

Now consider their age after 10 years (considering there is no change in population ) , total age of the 2 people be 20 and 40

Average age of the 2 people in year 2 { after 10 years } is = 30


Since the probability of a person suffering from Sinusitis remains same irrespective of age , thus it will be same and it increases from 20 years in year 1 to 40 years in year 2

Further it is given that -


Suppose the incidence rates for both arthritis and high blood pressure be 10% of the entire population in year 1 ,
According to the problem the incidence rates for both arthritis and high blood pressure will be 15% of the entire population in year 2

The above 2 statement simply demonstrates the increase in rate in incidence rates for both arthritis and high blood pressure with age and you can not simply claim that Sinusitis is more common than arthritis and high blood pressure
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could someone explain why its not B? The premise says that arthritis is the 2nd most common overall. Arthritis becomes more common as age increases. So if the avg age of population will increase, won't arthritis increase bc it will happen more often?

so if 60% of 60 year old have it now, 70% of 70 year olds and 80% of 80 year olds, if there will be more 80 year olds, doesn't that mean the % will go up because it skews to the higher end?

In ranking:
Sinusitis
Arthritis
High BP

Incidences of both, Arthritis and high BP increase with age. What if high BP incidence increases much more with age?

For arthritis: 60% of 60 year old have it now, 70% of 70 year olds and 80% of 80 year olds
For high BP: 50% of 60 year old have it now, 75% of 70 year olds and 95% of 80 year olds

We don't know the rate at which the incidence increases in the two diseases. So option (B) is not NECESSARILY true.

VeritasKarishma, even though I was stuck on C for a while, for C to be concluded, we would have to assume that sinusitis is an untreatable lifelong disease else if people infected within the time frame 1987-2000 are treated, the average age of people infected with sinusitis wouldn't necessarily increase. Please help me here??

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The argument tells us that sinusitis is a "chronic" disease. That pretty much implies that it continues for a very long time. Hence, we don't need to worry about people getting cured!

Premise :
1. In 1987 sinusitis was the most common chronic medical condition in the United States,
2. followed by arthritis and high blood pressure, in that order. (Arthritis is 2nd and high blood pressure is 3rd)
3. The incidence rates for both arthritis and high blood pressure increase with age,
4. but the incidence rate for sinusitis is the same for people of all ages.
5. The average age of the United States population will increase between 1987 and 2000.

So, what can we conclude?
1. Definitely incidence of Arthritis and High blood pressure is going to increase as average age is increasing. But can arthritis and blood pressure surpass sinusitis? There is no such evidence in the premise.
2. Incidence of Sinusitis is going to be nearly same as it doesn't depend on the age. Since average age is increasing, so definitely the average age of people with sinusitis will increase.

Options :

A. Sinusitis will be more common than either arthritis or high blood pressure in 2000.
Anything is possible. If the margin between sinusitis and arthritis or High BP is less, they may surpass the incidence of sinusitis. If the margin between sinusitis and arthritis or High BP is big, they may not surpass the incidence of sinusitis.

B. Arthritis will be the most common chronic medical condition in 2000.
Similar to reasoning in A, we can't be very sure which disease will be the most common though we definitely know that incidence of arthritis and high BP will increase.

C. The average age of people suffering from sinusitis will increase between 1987 and 2000.
This is correct for sure. Since the average age of the United states population will increase from 1987 to 2000. And the incidence rate of Sinusitis is same for all the ages , hence the average age of people suffering from sinusitis will surely increase between 1987 and 2000.

D. Fewer people will suffer from sinusitis in 2000 than suffered from it in 1987
Since incidence rate of sinusitis doesn't depend on the age, the number of people suffering from sinusitis will be nearly same if the population is nearly same. There may be fewer people or more people depending on the population decrease or increase respectively. We actually don't know about the population scenario here.

E. A majority of the population will suffer from at least one of the medical conditions mentioned above by the year 2000.
Ahhhhh... Nothing is indicating in this direction. According to the premise incidence of arthritis and high BP will surely increase but we don't know how much population will suffer.

In 1987 sinusitis was the most common chronic medical condition in the United States, followed by arthritis and high blood pressure, in that order. The incidence rates for both arthritis and high blood pressure increase with age, but the incidence rate for sinusitis is the same for people of all ages. The average age of the United States population will increase between 1987 and 2000.

Which of the following conclusions can be most properly drawn about chronic medical conditions in the United States from the information given above?

Was slightly confused between A and C, and then came up with a simple enough solution. Posting my solution, so that others can benefit
Given that average age of the population will increase, what must be true?

To understand this better, consider the simplest way for average age to increase - no new people are born and no people die. Automatically, with time, the average age will increase because the numerator will increase with each passing year, while the denominator will not.

This means all the people who had sinusitis will effectively get older (25 year olds will turn 38, 38 year olds will turn 51 and so on), hence the average age will increase.

Hi VeritasKarishma,

Thanks for your explanations above.
Is it right to conclude that average age of each group will go up anyway.
Sinus incidence is the same. Avg age of population increases. So sinus group increases.
Arthritis and HBP incidence will increase and become more common because avg age will increase and so avg age of their individual groups will increase too.

For option C, I could argue that people who had sinusitis in 1987 were more evenly spread out. now In 2000 people with lower ages were the ones affected more than the older ones so eventually the average could remain same or even decrease.

The premise doesn't mention anything about Sinusitis being even spread out it only mentions the incidence rates.

Can somebody shed light on where I am going wrong with my reasoning.

This is not necessary. It depends on why the avg age increases.
Under extreme circumstances, we can make a case that number of old people may stay the same but no new babies are born. So this increases the avg age. So avg age of arthritis and HBP may stay the same.

Say there are 10 people in every age range (0 - 10, 11 - 20 and so on till 90 years). Every 10 years, they graduate to the next range. If no new babies are born, we just won't find any in 0-10 range but number of people in other ranges will stay the same. Since arthritis and HBP afflict only the old, their avg age may stay the same.