Sunday, 24 July 2011

4 Significant Figures

1. Any digit that is not zero is significant. 1234.56 6 significant figures 
1234.56 6 significant figures
2. Zeros between non-zero digits are significant.
1002.5 5 significant figures
3. Zeros to the left of the first non-zero digit are not significant.
000456 3 significant figures
0.0056 2 significant figures
4. If the number is greater than one (1), then all zeros to the right of the decimal point are significant.
457.12 5 significant figures
400.00 5 significant figures
5. If the number is less than one, then only zeros that are at the end of the number and between non-zero digits are significant.
0.01020 4 significant figures
6. For numbers that do not contain decimal points, the trailing zeros may or may not be significant. In this course assume the digits are significant unless told otherwise.
1000 1, 2, 3, or 4 significant figures. UNCLEAR assume 4 in calculation
0.0010 2 significant figures
1.000 4 significant figures
7. Assume defined and counted quantities have an unlimited number of significant figures.
NOTE: It is much easier to count and keep track of significant figures if the number is written in scientific notation.
By Pravetha Nair

Mathematics as science



Carl Friedrich Gauss, himself known as the "prince of mathematicians", referred to mathematics as "the Queen of the Sciences".
Carl Friedrich Gauss referred to mathematics as "the Queen of the Sciences". In the original Latin Regina Scientiarum, as well as in German Königin der Wissenschaften, the word corresponding to science means a "field of knowledge", and this was the original meaning of "science" in English, also. Of course, mathematics is in this sense a field of knowledge. The specialization restricting the meaning of "science" to Natural science follows the rise of Baconian science, which contrasted "natural science" to scholasticism, the Aristotelean method of inquiring from first principles. Of course, the role of empirical experimentation and observation is negligible in mathematics, compared to natural sciences such as psychology, biology, or physics. Albert Einstein stated that "as far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality."
Many philosophers believe that mathematics is not experimentally falsifiable, and thus not a science according to the definition of Karl Popper. However, in the 1930s Gödel's incompleteness theorems convinced many mathematicians that mathematics cannot be reduced to logic alone, and Karl Popper concluded that "most mathematical theories are, like those of physics and biology, hypothetico-deductive: pure mathematics therefore turns out to be much closer to the natural sciences whose hypotheses are conjectures, than it seemed even recently." Other thinkers, notably Imre Lakatos, have applied a version of falsificationism to mathematics itself.
An alternative view is that certain scientific fields (such as theoretical physics) are mathematics with axioms that are intended to correspond to reality. In fact, the theoretical physicist, J. M. Ziman, proposed that science is public knowledge and thus includes mathematics. In any case, mathematics shares much in common with many fields in the physical sciences, notably the exploration of the logical consequences of assumptions. Intuition and experimentation also play a role in the formulation of conjectures in both mathematics and the (other) sciences. Experimental mathematics continues to grow in importance within mathematics, and computation and simulation are playing an increasing role in both the sciences and mathematics, weakening the objection that mathematics does not use the scientific method
The opinions of mathematicians on this matter are varied. Many mathematicians feel that to call their area a science is to downplay the importance of its aesthetic side, and its history in the traditional seven liberal arts; others feel that to ignore its connection to the sciences is to turn a blind eye to the fact that the interface between mathematics and its applications in science and engineering has driven much development in mathematics. One way this difference of viewpoint plays out is in the philosophical debate as to whether mathematics is created (as in art) or discovered (as in science). It is common to see universities divided into sections that include a division of Science and Mathematics, indicating that the fields are seen as being allied but that they do not coincide. In practice, mathematicians are typically grouped with scientists at the gross level but separated at finer levels. This is one of many issues considered in the philosophy of mathematics.

by Nadhirah

Statistics III


1. Data can be grouped into classes such as 1-5, 6-10, 11-15, ...
          Each class is known as a class interval

2. Range of the class interval is the difference between the smallest and the largest values.
    Range of class interval = Upper limit – Lower limit
3. For a class interval such as 1-5, the number 1 is called the lower limit and the number 5 is called the upper limit. 0.5 is the lower boundary and 5.5 is the upper boundary.
4.   4.  Class size or size of the class interval = Upper boundary – Lower boundary
5.   5.  Modal class is the class with highest frequency.
6.   6.  Midpoint of a class = Lower limit + Upper limit
                                                                2
1.    7.  Mean of a grouped data,     where f is its frequency and x is the midpoint of a class. ∑ means ‘sum of’.

8.  Histogram is a graphical representation of a frequency distribution.
1.       Horizontal axis can be labeled with midpoints or class boundaries or class intervals.
9. Frequency polygon is another graphical representation of a frequency distribution.   
10. The cumulative frequency of a data or a class interval in a frequency table is the sum of its frequency  and the total frequency of the entire class interval before it.

11. An ogive or cumulative frequency curve is a graphical representation of a cumulative frequency table.

1.       12. For ungrouped data, Range = Largest value – Smallest value
For example: 2, 4, 1, 8, 10, 7, 13, 5
Range = 13 – 1 = 12
For grouped data, Range = Midpoint of the last class interval – Midpoint of the first class interval
For example:
Mass (g)
  4 - 8
9 - 13
  14 - 18
19 - 23
24 – 28
Frequency
     3
    6
      12
     5
     2


Range   = 24 + 28    _    4 + 8
                      2                   2
              = 26 – 6  
              = 20
by: Mawar Ayu