
static  using_attempts_lang_string ($whichattempts) 
 Given a particular quiz grading method return a lang string describing which attempts contribute to grade.


static  using_attempts_string_id ($whichattempts) 
 Given a particular quiz grading method return a string id for use as a field name prefix in mdl_quiz_statistics or to fetch the appropriate language string describing which attempts contribute to grade.



int const  TIME_TO_CACHE = 900 
 previously, the time after which statistics are automatically recomputed.



core progress base  $progress 

◆ attempt_counts_and_averages()
quiz_statistics\calculator::attempt_counts_and_averages 
( 
 $quizid, 


core\dml\sql_join  $groupstudentsjoins ) 

protected 
◆ calculate()
quiz_statistics\calculator::calculate 
( 
 $quizid, 


 $whichattempts, 


core\dml\sql_join  $groupstudentsjoins, 


 $p, 


 $sumofmarkvariance ) 
Compute the quiz statistics.
 Parameters

int  $quizid  the quiz id. 
int  $whichattempts  which attempts to use, represented internally as one of the constants as used in $quiz>grademethod ie. QUIZ_GRADEAVERAGE, QUIZ_GRADEHIGHEST, QUIZ_ATTEMPTLAST or QUIZ_ATTEMPTFIRST we calculate stats based on which attempts would affect the grade for each student. 
core\dml\sql_join  $groupstudentsjoins  Contains joins, wheres, params for students in this group. 
int  $p  number of positions (slots). 
float  $sumofmarkvariance  sum of mark variance, calculated as part of question statistics 
 Return values

calculated\$quizstats  The statistics for overall attempt scores. 
◆ get_cached()
quiz_statistics\calculator::get_cached 
( 
 $qubaids  ) 

Load cached statistics from the database.
 Parameters

 Return values

calculatedfalse  The statistics for overall attempt scores or false if not cached. 
◆ get_last_calculated_time()
quiz_statistics\calculator::get_last_calculated_time 
( 
 $qubaids  ) 

Find time of nonexpired statistics in the database.
 Parameters

 Return values

intbool  Time of cached record that matches this qubaid_condition or false is non found. 
◆ median()
quiz_statistics\calculator::median 
( 
 $s, 


 $fromqa, 


 $whereqa, 


 $qaparams ) 

protected 
◆ sum_of_powers_of_difference_to_mean()
quiz_statistics\calculator::sum_of_powers_of_difference_to_mean 
( 
 $mean, 


 $fromqa, 


 $whereqa, 


 $qaparams ) 

protected 
Fetch the sum of squared, cubed and to the power 4 differences between sumgrade and it's mean.
Explanation here : http://docs.moodle.org/dev/Quiz_item_analysis_calculations_in_practise #Calculating_Standard_Deviation.2C_Skewness_and_Kurtosis_of_grades_for_all_attempts_by_students
 Parameters

$mean  
$fromqa  
$whereqa  
$qaparams  
 Return values

stdClass  with properties power2, power3, power4 
◆ using_attempts_lang_string()
static quiz_statistics\calculator::using_attempts_lang_string 
( 
 $whichattempts  ) 


static 
Given a particular quiz grading method return a lang string describing which attempts contribute to grade.
Note internally we use the grading method constants to represent which attempts we are calculating statistics for, each grading method corresponds to different attempts for each user.
 Parameters

int  $whichattempts  which attempts to use, represented internally as one of the constants as used in $quiz>grademethod ie. QUIZ_GRADEAVERAGE, QUIZ_GRADEHIGHEST, QUIZ_ATTEMPTLAST or QUIZ_ATTEMPTFIRST we calculate stats based on which attempts would affect the grade for each student. 
 Return values

string  the appropriate lang string to describe this option. 
◆ using_attempts_string_id()
static quiz_statistics\calculator::using_attempts_string_id 
( 
 $whichattempts  ) 


static 
Given a particular quiz grading method return a string id for use as a field name prefix in mdl_quiz_statistics or to fetch the appropriate language string describing which attempts contribute to grade.
Note internally we use the grading method constants to represent which attempts we are calculating statistics for, each grading method corresponds to different attempts for each user.
 Parameters

int  $whichattempts  which attempts to use, represented internally as one of the constants as used in $quiz>grademethod ie. QUIZ_GRADEAVERAGE, QUIZ_GRADEHIGHEST, QUIZ_ATTEMPTLAST or QUIZ_ATTEMPTFIRST we calculate stats based on which attempts would affect the grade for each student. 
 Return values

string  the string id for this option. 
◆ TIME_TO_CACHE
int const quiz_statistics\calculator::TIME_TO_CACHE = 900 
previously, the time after which statistics are automatically recomputed.
 Deprecated
 since Moodle 4.3. Use of precomputed stats is no longer timelimited.
 Todo
 MDL78091 Final deprecation in Moodle 4.7
The documentation for this class was generated from the following file:
 mod/quiz/report/statistics/classes/calculator.php