When you have historic data and you have to forecast about some variables?

<p><strong><em>1. Utilize the simple average methods.</em></strong></p> <p><strong><em>2. Utilize the trend methods.</em></strong></p> <p><strong><em>3. Utilize the knowledge of the business.</em></strong></p> <p><strong><em>4. Combinations of above.</em></strong></p>