Hopefully, you decided that the first statement is not true. It is an opinion and a biased one at that. It is also extreme in that it makes a generalisation. Some Scotsmen may be tight with their money but certainly not all Scotsman.
The first statement ("Scotsmen are tight with their money.") is not true.
The second statement ("Scotsmen are more likely to die of heart disease than Englishmen.") is true. Notice that is not specific - not every Scotsman will die of heart disease nor will every Englishman be free of heart disease.
I know the second statement is true because it is based upon science.

Scientists and philosophers seek truth but rarely in the same way.
This leads to another part of our definition - that science is knowledge gained by being, "tested through the scientific method."
Putting these thoughts together we will agree that
science is knowledge covering general truths tested through the scientific method.

But, what is the "scientific method"?

The scientific method is a sequence of steps that science uses to try to arrive at the truth. Fundamental to the scientific method is the hypothesis (plural hypotheses). A hypothesis is a tentative assumption made in order to draw out and test its logical or empirical consequences. Scientists test their assumptions, philosophers do not.

Scientists put forward a hypothesis as an idea that might explain an observation or provide an understanding of a phenomenon. And then they test it. Figure 1 illustrates the scientific method. You often start from an accumulated base of scientific data. From that information you develop a hypothesis to test. The testing is done by experimentation and observation. The new data collected from the testing is often used to revise the hypothesis and further experiments are done. Ultimately, a conclusion is drawn from the experiments and that conclusion might well be that the hypotheses (including the updated ones) are wrong!

This leads to an important point about a scientific hypothesis - it MUST be "falsifiable". That means a scientific hypothesis must have some feature about it that would allow someone (a careful experimenter or observer) to prove the hypothesis false.

That might seem a strange requirement but it is very important.
For example, I might make up the silly hypothesis that the Earth's core is made of chocolate. You would have a difficult time proving me wrong because you cannot visit the Earth's center in order to get a sample. For hundreds of years I could claim (unscientifically) that the Earth's core was chocolate and no one could prove me wrong.
You might be surprised to know that modern techniques in geophysics allow scientists to show that the Earth does not have a chocolate center. Measurements of the shock waves (produced by earthquakes) as they pass through the center of the Earth create a pattern that rules out a substance like chocolate. Indeed, the shock waves are more consistent with an Earth's core made of iron or nickel.
That means my silly hypothesis has actually become testable!
Think about that. My silly hypothesis was "unscientific" for hundreds of years but the 20th century science of geophysics progressed to the point that my hypotheses could actually be tested. That means 20th century technology made my silly hypothesis a scientific one. It's still silly but now it's testable and can be shown to be false. To put it another way, my silly hypothesis has been disproven by observations of shock waves using modern technology.

The "falsifiablity" of a scientific hypothesis is important.
It is the ability to prove a hypothesis wrong that makes it a scientific hypothesis. Philosophers may argue about how many angels can dance on the head of a pin, but scientists understand that there is no way to disprove any number of angels on a pin. There is no method to count angels. Therefore any hypothesis about the number of angels dancing on a pin is not a scientific hypothesis. It cannot be proven wrong. You might as well argue over how many pinhead philosophers can dance on an angel!
Forming a falsifiable hypothesis is not easy but it is required as part of the scientific method in order to discover the truth.

Try this (classic) question about truth.

Is it true, scientifically true, that all swans are white?

1. Yes, (all swans are white).

2. No, (not all swans are white).