Verifying is about checking the accuracy of data. But 'accuracy' is a broad term and can be taken to mean a variety of different things to different people. So let's consider the meaning of verifying, by looking firstly at how scientists check for accuracy.

During project work in Science at school or college, for instance, you are encouraged to evaluate the observations made by other people in your class, or in the media, for instance: "How reliable is the observation?" is the common question in this case. The answer to this question, of course, depends on a number of aspects: the identity of the observer; their level of experience; the regularity of their work in this field; and their subject knowledge.

Once these questions are answered satisfactorily, the teacher may then allow you to continue to rely on the original observation, and use it as the basis for analysis in your project. Throughout the scientific process, all data should be scrutinised and verified, even if it came from primary sources.

Some standard questions that you should ask at the outset, in order to verify data are listed below:

• Do you trust the observations you've obtained?
• How do you decide when you can trust information?
• Do you place more confidence in certain sources of information - books, newspapers, people?
• Do you believe what you read, regardless of the source?
• When before have you seen examples of misinformation?

Our need for simple answers to our problems is what scientists are trained to beware of; but in business and economics, as in everyday life, our desire for an easy life can be taken advantage of by marketing organisations, in advertising and promotions, such as price discount campaigns.

A £9.99 price tag suggests to us that the price belongs to the 900 pence group of numbers, and not the 1000 pence group to which it is actually closer. Psychological pricing is widespread, as any look at price tags in any shopping centre will tell you.

But maybe there's another reason for the '99p' tag. There must be a recorded transaction in a shop or restaurant, in order for us as customers to get our change. To pass us the change, the cashier or shop assistant has to key-in or scan the sale; the transaction then goes through the books; you get a receipt; and, crucially, the shop assistant can't just pocket the £10.

Of course, the shop assistant could just take into work every day a pocketful of 1 pence pieces, but then the in-store CCTV would probably give them away - even if the noise and discomfort every time they walked, didn't!

But this whole question of verifying gets a bit more complex than this £9.99 or £10 example suggests.

It's called 'price pointing' and it's about what we as consumers expect to pay, based on our previous experience. In the UK, research carried out on price pointing, notably, a case study on the demand for tights (pantyhose in the USA) showed that there were peaks in demand at particular price points that the buyer anticipated.

These points were seen to be at prices like 59p, 99p, £1.29, and so on. At other prices in between these points, demand was considerably lower, even though the goods concerned were the same.

UK wine sellers adopt this principle too. They suggest that sales at different prices, even where the difference is only 1 pence or so, actually result in dramatically different sales volumes.

Another interesting area of consumer reaction to price is the phenomenon of the 'Just Noticeable Difference' (JND). There is a JND below which consumers will not react to a price increase. Typically this is regarded as being 5%,. So, you can increase prices above previous levels by less than the JND, without your customers complaining. Equally, when you are cutting prices, what's the point of discounting by less than 5%, if your customers won't notice the difference?

There is a worksheet on verifying data that you may like to have a go at to check you understand the issues.

As with much of what you study in Business or Economics, it is important to remember that no issue, such as JND, can be seen in isolation. The role of price elasticity of demand must be taken into consideration here too. Bear in mind when you're thinking about JND, that if the good or service you are analysing is highly price elastic, then any change in price is likely to result in a proportionally larger change in quantity demanded. When a good or service is price inelastic, any price change is less likely to impact to the same degree on quantity demanded.