Error exponent is a way to measure how often mistakes happen when we are sending information from one place to another. Imagine that you want to send a message to your friend who is far away. You can send the message by writing it down and sending it in an envelope, or you can tell your friend the message over the phone.
When you send the message, there is a chance that it might not be received correctly. Maybe the envelope gets lost in the mail, or maybe there is static on the phone line and your friend can't hear you clearly. The error exponent tells us how likely it is that the message will be received incorrectly.
Think of it like a game. You have a bunch of balls, and you need to put them in a basket. Sometimes, you might miss and the ball won't go in the basket. The error exponent tells you how often this happens - if you have a high error exponent, it means you are missing a lot, and if you have a low error exponent, you are hitting the basket most of the time.
For example, if you are sending a message over the phone, the error exponent depends on how clear the connection is. If there is a lot of static, the error exponent will be high because there is a good chance that your friend won't hear you correctly. But if the connection is very clear, the error exponent will be low because the chances of a mistake are much lower.
In general, the lower the error exponent, the better. It means that the message is less likely to be received incorrectly, which is important if you are sending important information. So, people need to keep the error exponent as low as possible to ensure that the information is received without any mistakes.