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### Course: Digital SAT Math > Unit 7

Lesson 10: Evaluating statistical claims: medium# Data collection and conclusions — Harder example

Watch Sal work through a harder Data collections and conclusions problem.

## Want to join the conversation?

- It doesn't seem that hard, just really, really long.(61 votes)
- Anyone have a faster method? Spending the time to write out and plot those points seems too long to be viable during the SAT.(6 votes)
- Here's how I would've solved the problem:

I is correct, because there are only two players not born between January 1st and June 30th (the last two players).

II. is incorrect because I is correct.

III. is incorrect because the table doesn't say anything about the skill of the players.

IV. is correct. You can know that by counting the players who are born in 1987.

Thus, I would've solved this in about a minute. Maybe this question isn't that hard, after all. :)(23 votes)

- Choice number1 didn't convince me, what's the relationship between players being part of the team and being born between January 1 and June 30?(12 votes)
- There is an association, and it is that more people are born in the first half of the years so that's the association. And that is why number 1 is also correct.(1 vote)

- It's 2007 in the question, but he says 2017.(4 votes)
- I think I it should add approximately in front of "42%",then the answer will be B.(3 votes)
- It sounds like it should be, but I actually don't think it would be. Because there is a chance that out of the 500 people randomly picked, all of them were political extremists or something and would support a policy no one else would, you can't say that anything
*must*be true. Approximately 42% would mean that choice B) is very likely to be true, but not that it is true in all cases. This is the same in basically every SAT question like this, except if they give you a confidence interval in the question.(7 votes)

- Is there a faster method of solving for this type of problem?(6 votes)
- Does it mean there is an association between two events if the number seems like there is one?(5 votes)
- if you notice, 10 out of 12 were born in the first half of a year. and 10/12 is about 85% which is pretty high for data based on just 12 people(1 vote)

- I was yelling at my screen halfway through the video that it was C lol took forever(4 votes)
- where can i find videos that will help me understand this concept(4 votes)
- Him saying "I'm feeling queasy about that" is not helpful.

can someone explain why I and II are not correct?

we don't have an exact population number. It just says a large city, so we assume 500 people is a good about of participants to represent that city.

And we know that 42% is not definitive but it is an approximation.(1 vote)- I can see your point about the 500 people being representative.

The issue is what you referenced at the end. You are assuming an approximation; however, choices I and II don't mention "approximate" or "around".

For example, if they added a margin of error or used those words, it could have worked because it was a random sample.

For II, again with the lack of the word approximate, in that group there could have been 40.5% who supported it.

Dr. Ihrig(6 votes)

## Video transcript

- [Narrator] A polling agency
recently surveyed 500 adults who are selected at
random from a large city and asked each of the adults whether they supported
a new federal policy. Of those surveyed, 42% responded that they
support the new policy. Based on the results of the survey, which of the following
statements must be true? So, pause this video and see
if you can figure this out. All right, now let's work
through this together. So, let's look at the statements. So, statement one, of all
the adults in the city, 42% support the new federal policy. Let's see, they took
a sample of 500 adults who are selected at random and 42% of them supported the policy. So, of all the adults in the city, 42% support the new federal policy. Well, we don't know that for sure 42% would be a pretty good estimate of it based on the sample. So, I'm feeling a little
bit queasy about choice one, let's try to see choice two, If 500 different adults selected at random from the same city were surveyed, 42% of them would respond that they support the new federal policy. While I'm feeling queasy
about that as well because once again, it's
likely to be close to 42, but it could be 43%. We can might've just gotten
lucky with the number of people who supported the federal policy it could be a lot lower or we could have gotten unlucky and it could be a lot higher. So, I'm feeling queasy
about that one as well. So let's see, if 500
adults selected at random from a different city were surveyed, 42% of them would
respond that they support the new federal policy. Well, that one feels actually
the hardest one to believe, because now you're looking at
a completely different city that it could have very different views, I don't like that one either. So actually, I like none of these choices, you don't know just based
on the sample of 500 and you got 42% of them supporting. You don't know that every
time you get a sample that you're gonna get exactly 42. You also don't know that it's exactly 42 of the entire population in the city. And you definitely don't know that if you took 500 adults
at random from another city, that it would be 42%. So, I would say none.