udacity statistics

Why does we make statistics so hard for our students?(Warning:long and slightly wonkish)If you ' re like me, you're continually frustrated by the fact that undergraduate students struggle to understand statistics . Actually, that's putting it mildly:a large fraction of undergraduates simply refuse to understand statistics; Mention a requirement for statistical da

When the analyzer looks for a path, it does not count the number of rows and ranges of values contained in the index every time, instead, the information is created and updated based on certain conditions and saved to the database. This is the so-called statistical information. How to view statisticsIt is very simple to view SQL Server statistics. Run the following command:DBCC SHOW_STATISTICS ('table name', 'index name ') The result 1 is displayed.

Reprint please indicate the source: a column of Maple Leaf In the previous article, we introduced the hot fixes in the Android community, and introduced several popular heat repair frameworks, as well as their pros and cons, and introduced the practice of thermal remediation in their own projects. At present, the main principle of heat repair is actually divided into two, one is through the use of DEX load order to achieve thermal repair function, one is through the native layer to achieve

Tags: arc requires IDE number Server index execute execution plan log The source of this article: http://www.cnblogs.com/wy123/p/6008477.html For statistics on the number of rows of data estimates, previously written on the non-related columns (separate or separate index columns) of the algorithm, refer to here. 　　Today, let's write the statistical information on the calculation methods and potential problems of the composite index at the time of est

1. Concept 1. Dynamic sequence statistics dynamic sequence statistics means that any sequence statistics in a dynamic unordered set can be determined within O (lgn) time. 2. the base array structure is a red-black tree. The fields of each tree node include: Key [X], color [X], left [X], right [x] 3. additional information size [x]: number of internal nodes (inclu

Original article: fast, easy, realtime metrics using redis bitmaps Http://blog.getspool.com/2011/11/29/fast-easy-realtime-metrics-using-redis-bitmaps) The important statistical data of getspool.com is calculated in real time. Redis's bitmap allows us to perform similar statistics in real time and greatly save space. In a simulated environment where 0.1 billion million users are simulated, the typical statistical consumption of dailyunique users on a

\uff0c\u60a8\u6307\u5b9a\u7684\u7528\u6237\u7a7a\u95f4\u4e0d\u5b58\u5728 This code for the sake of simplicity, no longer httperror those ID categories, directly stored in the following 5 files file1 = ' Ruisi\\correct_re.txt ' file2 = ' ruisi\\errtime_re.txt ' file3 = ' ruisi\\notexist_re.txt ' file4 = ' Ruisi\\unkownsex_re.txt ' file5 = ' Ruisi\\httperror_re.txt ' You can look at the output log records and how many httperror of data are processed in total. "D:\Program Files\python27\pytho

Curl simulated access page-is the third-party statistics like cnzz unavailable? For example, I have a website www.xxx.com, which uses cnzz access statistics js code. I tested it on my local machine and used curl to simulate access to www.xxx.com, I cannot see my access records in the cnzz statistics list. Is there any way to make cnzz

Statistics on high-speed network traffic and Linux traffic in linuxNetpps. sh counts the data volume per second, including receiving (RX) or sending (TX) Netpps. sh eth0#! /Bin/bashINTERVAL = "1" # update interval in secondsif [-z "$1"]; then echo usage: $0 [network-interface] echo e.g. $0 eth0 echo shows packets-per-second exitfiIF = $1 while truedo R1 = 'cat/sys/class/net/$1/statistics/rx_packets 'T1 = 'c

This script permit executes the sp_updatestats in all databases at same time. First I create the Stored Procedure abve in an admin database, for sample I create one database with Admin name where I put all administration objects create for me. you can create this SP in exist dB, if you want. Now you can execute this SP in query analyzer or create a job to automate this operation. to execute this, call the next commands: Use admin -- or the name of database where you create this SPExec spupdates

Knowledge Points:1) arrayAn array is a variable used to store a series of values that can be indexed to access the values of the array.An array in awk is called an associative array because its subscript (index) can be a number or a string.Subscripts are often called keys, and the keys and values of an array element are stored in a table inside the awk program, which takes the hash algorithm, so the array elements are randomly ordered.Array format: Array[index]=value1, nginx log analysisLog form

(192.168.119.9). The 00:00~24:00 of the server on January 1, 2013, the acquisition unit is minutes, a total of 1440 data for quantitative analysis.The main purpose of this paper is to predict the future development trend of user access frequency frequency_user. Therefore, the relationship between user access frequency Frequency_user, memory utilization MEM, hard disk utilization disk and CPU utilization needs to be considered. The data file information is merged into a new data file, the data c

How does PHP make website access information statistics? This paper mainly introduces PHP access information statistics class compete API usage, examples of PHP using curl to get compete statistics website information skills. We hope to help you. The example in this article is about PHP's access to the Web site statistics