How do I calculate measures of central tendency and dispersion?

If you are given a mean problem with a frequency, all you have to do is to multiply to get your fx. Example: Ages of students: 5,3,2,1. No of students:10,4,7,3. The no of students represents the frequency (how many times the student with a certain age occur). I will name the ages of students with X. All I have to do now is to get my FX which is gotten by multiplying the nos under X with their corresponding frequency. If you are given a question on mode, all you have to do is to find the one with the most occurrence. Example: 5,5,4,6,4,6,7,6,7,5,5,3,2,5. The number that occurs most is 5. So 5 is the mode because it occurs more than the rest numbers. If you are given a range question, you just have to subtract the smallest number from the highest number. Example: 5,9,3,2,1,7. The range will be 7 - 1 =6. So the range is 6. Just remember it is the HIGHEST VALUE SUBTRACTING THE SMALLEST VALUE. If you are given a median question, all you have to do is find the middle number. You can be given scattered numbers to find the median. First of all, arrange the numbers in ascending order (from the lowest to the highest) or descending order (from the highest to the lowest) then find the middle number. Only then can you get your median. In some occasions you can get two middle numbers all you have to do is to add the numbers together and divide by 2. You can ask more questions. I am here to help.