What is really needed is the distance from each grade to the mean not the difference. You could take the absolute value of each difference and then calculate the mean. This is called the mean deviation, i.e. mean deviation = , where n is the number of students in the class. For class 1 this is 64/5 = 12.8.
1. Determine if there is a roof leak. Look for mold or mildew in attics or on walls. Look for discoloration on ceiling tiles or drywall. Look for wet, moist and rotting wood in crawl spaces, around chimneys or other additions, such as skylights and vents.. Check the attic for dyed areas. Follow the dye path from where it begins to where it comes out to find the leak. There may be multiple points of entry, so if you find one point, continue to search thoroughly until you are satisfied that there are no more leaks.
Replace a Flapper Valve. You can perform a simple dye test to check for leaks in the flapper valve. Place dye tablets or a couple drops of food coloring into the tank water to give the water color. If the colored water appears in the bowl within 15 minutes, there is a leak in the flapper valve.sing your water meter you can perform a simple leak check with the following steps: 1  Make sure all water is turned off inside and outside the home. 2  Record the reading of the water meter, and wait 15 minutes. 3  Record the reading of the meter again.