Welcome to Medium, where words matter. We’ll deliver the best stories forex sederhana ideas on the topics you care about most straight to your homepage, app, or inbox. Moving Average The Moving Average Technical Indicator shows the mean instrument price value for a certain period of time. When one calculates the moving average, one averages out the instrument price for this time period.
As the price changes, its moving average either increases, or decreases. The only thing where moving averages of different types diverge considerably from each other, is when weight coefficients, which are assigned to the latest data, are different. In case we are talking of Simple Moving Average, all prices of the time period in question are equal in value. The most common way to interpreting the price moving average is to compare its dynamics to the price action. When the instrument price rises above its moving average, a buy signal appears, if the price falls below its moving average, what we have is a sell signal.
This trading system, which is based on the moving average, is not designed to provide entrance into the market right in its lowest point, and its exit right on the peak. It allows to act according to the following trend: to buy soon after the prices reach the bottom, and to sell soon after the prices have reached their peak. Moving averages may also be applied to indicators. That is where the interpretation of indicator moving averages is similar to the interpretation of price moving averages: if the indicator rises above its moving average, that means that the ascending indicator movement is likely to continue: if the indicator falls below its moving average, this means that it is likely to continue going downward. This value is then divided by the number of such periods. N — number of calculation periods.
Exponentially smoothed moving average is calculated by adding of a certain share of the current closing price to the previous value of the moving average. With exponentially smoothed moving averages, the latest close prices are of more value. P — the percentage of using the price value. In the case of weighted moving average, the latest data is of more value than more early data.
Review your answers, feedback, and question scores below. In a payroll system, it is desirable to have an entity called DAY with a holiday attribute when you want to track special holiday dates. If you have an entity that a DATE attribute, and other attributes that track characteristics of the date, you should create a DAY entity. Refer to Section 8 Lesson 2. All systems must have an entity called WEEK with a holiday attribute, so you know when to give your employees a holiday.
How do you know when to use the different types of time in your design? It depends on the functional needs of the system . You would first determine the existence of the concept of time and map it against the Greenwich Mean Time. The rules are fixed and should be followed. Formal rules exist for drawing ERD’s. You must always follow them, even if it results in an ERD that is difficult to read.
Refer to Section 8 Lesson 4. In an ERD, it is a good idea to group your entities according to the expected volumes. By grouping high volume entities together, the diagrams could become easier to read. In an ERD, High Volume Entities usually have very few relationships to other entities.
You must make sure all entities of a proposed system can fit onto one diagram. It is not allowed to break up a data model into more than one diagram. Which of the following scenarios should be modeled so that historical data is kept? Refer to Section 8 Lesson 1. When modeling historical data the unique identifier is always made up of a barred relationship from the original two entities. Historical data must never be kept. You are doing a data model for a computer sales company where the price of postage depends upon the day of the week that goods are shipped.
So shipping is more expensive if the customer wants a delivery to take place on a Saturday or Sunday. What would be the best way to model this? Email current prices to all employees whenever a price changes. Use a Delivery Day entity, which holds prices against week days, and ensure the we also have an attribute for the Requested Delivery Day in the Order Entity. Allow them to enter whatever delivery charge they want. Update the prices in the system, print out the current prices when they change, and pin them on the company noticeboard.