1.2.3. Construction of frequency histograms of samples

To construct frequency histograms of samples in the main application form of STATISTICA it’s necessary to choose the function “Graphs”. In the window of this function we choose “2D graphs”, and in it – kind of graphical construction – “Histograms” – fig.1.10.

Fig. 1.10. Forms for the procedure of constructing frequency histograms

In the window “2D Histograms” task of attributes constructing histograms

• In option “Quick” we set:

- after pushing the buttion “Variables” – the name of the data sample, which was given to her (ATTENTION! Only one sample!);

- in the window “Graph type” - “Regular”;

- on activated (stands dot) position “Сategories” – set the number of sites that will be broken range of values ​​of the sample (recommended 5 : 7);

• In options “Additionally”:

- set in the window “Type of fitting ” the view – “Normal”.

- in the window “View type” we choose “Standard”.

After this press ОК.

Type frequency histogram approximation of the normal law distribution shown in Fig.1.11.

Fig.1.11.The result of constructing the frequency histogram

After performing last procedure is necessary to test the distribution belonging to other law. For the latter case, the in option "Advanced" must be set:

- in the window “View type” reserve “Standard”;

- in the window “Fitting type” use the program proposed various distributions.

1.2.4. Receiving of values ​​of statistical characteristics of sample data

In the main program window of STATISTICA at the upper panel we choose “Statistics” “Analysis/Descriptive statistics”, and in it – the command “Basic Statistics/Tables” – fig.1.12.

In the command window “Basic Statistics/Tables” choose the regime “Descriptive statistics”.

In the form of a procedural default attributes determine the statistical characteristics of the distribution laws by pressing the "Variables" in the names of samples that are investigated, mark all the names listed there (all 6 sets of data). In the option "Advanced" set a check in front of the necessary statistical characteristics, namely “Valid N”, “Mean” , “Standard Deviation”, “Variance” and “Minimum & Maximum” , after this press OК.

Fig. 1.12. Form of procedures for the statistical characteristics of the data

In the window, form of which is shown on fig.1.13, will appear the results of counting of ordered statistical characteristics of each data sample.

Fig. 1.13.The Form of calculated values ​​of the statistical characteristics of the data

1.3. The report of lw should contain:

1. Introduction

2. Prints:

• Initial data – arrays of data

• Time diagrams, values ​​of the production process for 6 months of the company;

• Frequency histograms for each sample;

• Tables of received values of statistical characteristics of each data sample

3. The results of stability values ​​of statistical estimates of the production rate.

Comments on this item

Stability values ​​of statistical characteristics of mathematical expectation, standard deviation and variance estimate as lack of deviation values ​​for each sample for the bound  5% from the average of all the samples.

4. Conclusions from the results obtained on qualitative characteristics of the process on the basis of stability, durability, accuracy and readiness