6-49
  The following shows the parameter data specification items that are different from list data 
specification.
  
  
  
  Calculation Result Output Example
  
  
  
  
  
  
  
u 2-Sample   t  Interval
   2-Sample  t  Interval  calculates the confidence interval for the difference between two 
population means when both population standard deviations are unknown. The  t  interval is 
applied to  t  distribution.
  
  Perform the following key operations from the List Editor.
  
        4(INTR)
        2(t)
        2(2-SAMPLE)
  
  7. Distribution    
  There is a variety of different types of distribution, but the most well-known is “normal 
distribution”, which is essential for performing statistical calculations. Normal distribution 
is a symmetrical distribution centered on the greatest occurrences of mean data (highest 
frequency), with the frequency decreasing as you move away from the center. Poisson 
distribution, geometric distribution, and various other distribution shapes are also used, 
depending on the data type.
  
  Certain trends can be determined once the distribution shape is determined. You can calculate 
the probability of data taken from a distribution being less than a specific value.
  
  For example, distribution can be used to calculate the yield rate when manufacturing some 
product. Once a value is established as the criteria, you can calculate normal probability when 
estimating what percent of the products meet the criteria. Conversely, a success rate target 
(80% for example) is set up as the hypothesis, and normal distribution is used to estimate the 
proportion of the products will reach this value.