3. NUMERICAL NUMBER

3. NUMERICAL NUMBER

1. PARAMETER

   • A measurable characterictic of a population.
   • STATISTIC - A measurable cahracteristic of a sample.

2. POPULATION MEAN

   • The sum of all the population values divided by the number of population values.

3. SAMPLE MEAN

   • The sum of all the sample values divided by the total number of sample values.

4. THE MEDIAN

   • The midpoint of the values after they have been ordered from the smallest to the higest, or the largest to the smallest.
   • PROPERTIES OF THE MEDIAN
     • 1. There is a unique for each data set.
     • 2. it is not effected by extremely large or small values and is theredore a valuable measure of central tendency when such value occur.
     • 3. it can be computed for ratio-level, interval-level and ordinal level data.
     • 4 it can be computed for an open-ended frequency distribution if the median does not lie in an open-ended class.

5. THE MODE

   • The value of the observation that appears most freequently.

6. THE GEOMETRIC MEAN

   • Useful in finding the average change of percentage, ratios, indexes or growth rates over time.
   • will always be less than or equal the arithmetic mean.

7. VARIANCE

   • The arithmetic mean of the squared deviations from the mean.

8. STANDARD DEVIATION

   • The square root of the variance.

9. CHEBYHEV'S TEOREM

   • For any set pf observation the proportion of the values that lie within k standard deviations of the mean.