+1-415-670-9189
info@expertsmind.com
Random integral numbers based on normal distribution
Course:- PHP Web Programming
Reference No.:- EM13502




Assignment Help
Expertsmind Rated 4.9 / 5 based on 47215 reviews.
Review Site
Assignment Help >> PHP Web Programming

Your task is to realize two additional data generation functions. Firstly, extend the system to generate random integral numbers based on normal distribution. You need to study Data Generator's structure and extend number generation type to activate normal distribution. The interface needs to obtain both mean and sigma as shown in Figure. Consider the code found 

coding.derkeiler.com/Archive/PHP/php.general/2007-12/msg00317.html

Notice that the return value of the above code is a floating value. You can round it to nearest integer by adding a "rounding option" to the interface.

1081_Random integral numbers based on normal distribution.png

Next, realize one form of skewed distribution that approximates Pareto Principle. Consider a skewed access pattern often evidenced in data applications such that s percent of accesses would go to (100 - s) percent of data items. For instance, a typical "80-20 rule" for 1000 accesses over 500 data items means that about 800 accesses (80% of accesses) go to a specific set of about 100 items (20% of data items). In our case, data generation should be based on independent repeated trials, not as all trials once in a batch. Hence, implementing strict Pareto Principle is difficult. Instead, we can approximate access pattern generation by the following method:

  • skew generation function receives a range r and a skew factor s as parameter, both of which are integers and r must be larger 1 while s must be between 50 and 100.
  • data elements are considered to have unique IDs in the range [1, r], in which elements are listed in an increasing order of IDs such as 123, ..., r.
  • skew generation function produces an integer value between 1 and r representing a data access in the following manner:

1. skewed access will go to the top portion of the elements, that is, those between 1 and t = r × (100 - s) / 100.

2. draw a random number p from uniform distribution between 0 and 99.

3. if p falls in less than s, i.e., [0, s - 1], the top portion of elements [1, t] is accessed.

4. otherwise the access goes to [t + 1, r].

Above illustration should be sufficient to provide you with the concrete requirement for the two frequently utilized data generation. Figure 1 and 2 shows interface and sample output respectively. In these figures, rounding to integer is applied automatically. A checkbox should be added to the interface so that users can choose whether values generated are rounded or not. Notice that this development is not from scratch, but is "reverse engineering" of already developed product. Addition of the above functions to Data Generator is easily done. You should look into the contents of docs/data_type.php.

573_Random integral numbers based on normal distribution1.png

The second task is to add more generation capabilities and/or tailor the built-in functionality of generator. This enables you to produce "all" the test data for the MySQL tables you produced in the previous assignment. You do not need to populate data to the tables in this assignment (which will be the task in the next assignment) but you must become able to generate all the realistic data required for the proposed information analysis. You are not allowed to use other software tools (such as Microsoft Excel) to generate data. You are not allowed to use "existing data" to skip this assignment. Any non-trivial extension from the statistical viewpoint concerning the data nature (like the above assigned functionality) will receive extra credit.




Put your comment
 
Minimize


Ask Question & Get Answers from Experts
Browse some more (PHP Web Programming) Materials
Create a web site for an apple farm. Create an HTML5 form allowing visitors to create an account with the site. Account details are to be stored in your MySQL database. Inform
Create a form that sends data to best_songs.php on a server. The form should have a text box for your name and a collection of at least four checkboxes representing kinds of s
Describe how cookies can be used to store information on a computer and how the information can be retrieved by a PHP script. Assume that cookies are not disab
Use the documents that are posted on share out. Many of them demonstrate very similar (or even the same) examples as what you are being ask to do for this assignment.
php mysql insertion form that will insert name in customer table and have product field that will be a dropdown menu getting product names from the product table database. Whe
What is the difference between "information-intensive goods" and "classic information goods"? How can a firm that find's itself on the losing side of network effects surviv
What is the goal of your website? What do you want people to learn, believe, or do after interacting with your website? Is your purpose narrow and specific enough that you can
Identify the errors in the HTML code provided in work.html and work.css (download attached ZIP). Correct the code and create HTML comments explaining why the original code w