Statstics Why AND WHAT?

Statstics Why AND WHAT?

1. The current review attempted a fraction replication of this work by investigating.

   • a) The general encounters of applied etymologists with perceptions, b) the fundamental factors that establish information from applied language specialists and perspectives toward measurements, c) factors that anticipate mindset toward perceptions and factual self-efficacy

2. Measures of central tendency

   • Measures of central tendency are statistical measures that are intended to summarize a set of values in a single value
     • the most used measures of central tendency are: mean, median, and mode.
   • Avarage or mean
     • the arithmetic average is represented by the Greek letter u
   • mean
     • the mean is expressed in the same unit as the original data: centimeters, hours, grams, etc.
   • Deviation
     • Is the difference between the value of the data and the mean.
   • Median
     • is the value of the variable that occupies the central position.
   • Mode
     • the mode is defined as the value of the variable that repeats the most. in a frequency polygon, the mode corresponds to the value of the variable.

3. The measure of dispersion: they intend to summarize in a single value the dispersion that a data set has, the most used measures of dispersion are: Range of variation. variance, standard deviation, coeficient of deviation.

   • Range of variation
     • the difference between the highest value and the lowest value.
   • Variance
     • it is represented with the symbol σ2 (sigma squared) for the universe or population and with the symbol (S2)
   • Standard deviation
     • is the root of the variance, is re´resesymbolnted by the symbol sigma o, when it belongs to a universe or population and by "s" when it belongs to the sample.
   • Coeffiicient of variation
     • It is a measure of the relative Coeficient of variation: Coefficient: the standard deviation of the sample expressed as a percentage of the dample mean.

4. Average in pooled data the formula is as follows

   • if the variable of interest is of a continuous type, it will be necessary to determine each interval. this value is called the classmark (Yc), if the variable is of a discrete type, the mode will be the variable (Yi) that has the highest absolute frequency.

5. Variance in group data

   • For the calculation of a variable in grouped data, the formula is used with the data of the example. Where the data is grouped in class intervals, we work with the classmark (yc) where the (Yc) is the midpoint of the interval.

6. The normal distribution

   • 1. describe the distribution of the variables studied and in particular of the numerical data. The behavior of these variables can be graphical.
   • the range of values is divided into intervals of equal length, representing on each interval a rectangle with an area proportional to the number of data in that range 1
   • The smooth "asymptotic" curve represents the theoretical distribution of the observed characteristics.

7. The standard error

   • The shape of the Gaussion bell depends on the parameters, the mean indicates the position of the bell so that for different values of the graph it is shifted along the horizontal axis. The standard deviation determines the degree of steepening of the curve.
   • the standard error measures the random error in a reported statistical data. the type of error caused by the random variation of the sample when reapinting a test under the same condition.