HOW TO ORGANIZE DATA
One way of organizing raw data or observations is through the use of frequency distribution table. One such example is a profile of cooperatives in a province which is given below:
|Initial Capital, in Pesos |Number of Cooperatives |
|Below 25,000 |43 |
|25,000 – 49,999 |28 |
|50,000 – 74,999 |17 |
|75,000 – and above |12 |
STEPS IN CONSTRUCTING A FREQUENCY DISTRIBUTION TABLE:
1. Obtain the number of class ...view middle of the document...
Construct the table.
With the interval size and the number of intervals known, we can construct the frequency distribution by first dividing the excess between the lowest and the highest ends of the data.
GRAPHICAL METHODS FOR DESCRIBING QUANTITATIVE DATA:
1) Frequency Histogram – a bar graph representation of a frequency distribution table. Marked along the horizontal axis are the class boundaries (CB). Frequencies are marked along the vertical axis. Each interval is drawn as a bar bounded or defined by the class boundaries and the corresponding frequencies.
2) Frequency Polygon – uses class midpoints (CM) to represent the intervals. Class midpoint is computed as the average of the lower class limit (LCL) and the upper class limit (UCL). Class limits are the visible limits of the intervals in the frequency distribution table.
NUMERICAL DESCRIPTIVE MEASURES
- are numbers that are used to create a mental image of a data set.
1) Measures of Central Tendency or Location:
The measure of central tendency is the point about which scores tend to cluster; a sort of average in a series. It is the center of concentration of scores in any set of data. It is a single number which represents the general level of performance of the group.
The three measures of central tendency in common use are: Mean, Median and Mode.
MEAN – is defined as the sum of the values in the data group divided by the number of values. The formula is:
where X = the raw data or observations
n = the number of observations or values
For grouped data which is in the form of a frequency table, the formula is:
where f = frequency of each class interval
x = class midpoints
n = total number of observations
MEDIAN – the middle value in an arrayed data (data which has been arranged in ascending order).
For grouped data, the formula is:
LCBmed = lower class boundary of the median class
n = number of observations
F = cumulative frequency of the class before the median class
fmed = frequency of the median class
I = class interval size
The median class is identified as the class whose cumulative frequency reaches n/2 first.
MODE – the...