Clinical sas interview questions for freshers –Part 1

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Clinical sas interview questions

Here we have provided a list of basic clinical SAS interview questions. These are the common questions usually asked in interview (especially for freshers). These question and answers are prepared from freshers point of view. Before attending an interview you must have at least below clinical sas interview questions and answers

Every sponsor company may not have this job vacancy(Usually MNC company have this department). Usually sponsor will outsource their work to CRO. Every Contract Research Organisation(CRO) have data management department. It includes Clinical SAS department. And this vacancy(Clinical SAS programmer) is available in this department.

Any life science graduate can learn Clinical SAS program to get a job. Clinical sas Interview questions are provided and given with a brief explanation. Due to length of this questions, clinical sas interview questions and answers divided in 3 parts. Questions and answers as follows.

1) What Is SAS?

Ans: SAS stands for the statistical analysis system or software. It is a tool for collecting, summarizing, analysing the data.it is used in the variety of domains like clinical, Banking, network marketing, Trading etc.

2) what is the use of _N_ and _Error_ in SAS?

Ans: _N_  and _Error_ is the automatic variables in SAS which created in the backend each one having its unique usages. _N_ is the number of iteration means how many times the data step or proc steps begins to execute.

And _Error_ shows the error present in the programme or not. It takes only two values 0 and 1.

If _Error_=1 then there is error present in the programme and if _Error_ =0 then there is no error present in the programme.

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3) what is the use of Proc means and by default which statistics we will get?

Ans: Proc means is the procedure in SAS which is used for finding the descriptive statistics.

By default, we will get N, minimum, maximum, mean, standard deviation.

 Syntax is as follows,

Proc means data = dataset name;

 Var variable_names;

Run;

Related: Medical representative interview questions

4) what is the use of SDTM and ADaM CDISC standard in the data management?

Ans: CDISC (clinical data interchange standard consortium) it the non-profitable organisation which defines the standards for industry drug submission Like SDTM (Study data tabulation model), AdaM (analysis dataset model, CDASH (clinical data acquisition standard harmonisation), SEND (standard for exchange of non-clinical data), LAB (laboratory dataset model), PRM (protocol representation model), ODM (operational dataset model) each standard having its unique specification. Standard implementation guides for each and every standard are created by CDISC team for easy drug regulatory submission.

SDTM is stands for study or standard data tabulation model which is use for the conversion of the Non-standard data into the standard form in the clinical domain. Because standard data is easy to analysis and it is easy for researcher to make valid interpretation from the standard data. The latest version of implementation guide for SDTM is SDTMIG v3.1.2.

ADaM is stands for the analysis dataset model. this standard is use for converting the SDTM standard dataset in to analysis ready dataset for the analysis purpose. The latest version of implementation guide for ADaM is AdaMIG v2.1.

5) How to combine the two or more datasets in SAS?

Ans: there are some methods available in SAS for combining the SAS datasets. Which is as follows

  • Concatenation: this method is used used to connect two or more dataset

The syntax is

Data Newdataset1_name;

 Set existingdataset1_name existingdataset2_name;

Run;

  • Interleaving: this method combines the sorted datasets according the sorted by variables.

The syntax is

Proc sort data=existingdataset1 out=existingdataset1_name;

 By Variables_name;

Run;

Proc sort data=existingdataset2 out=existingdataset2_name;

 By variables_name;

Run;

Data Newdataset_name;

 Set existingdataset1_name existingdataset2_name;

 By variables_name;

run;

  • Merging: this method combines the observations from two or more datasets into single observation in the new data set.

The syntax is

Proc sort data=existingdataset1 out=existingdataset1_name;

 By Variables_name;

Run;

Proc sort data=existingdataset2  out=existingdataset2_name;

 By variables_name;

Run;

Data Newdataset_name;

 merge existingdataset1_name existingdataset2_name;

 By variables_name;

run;

6) what is the SAS datasets variables attributes?

Ans: there are 5 SAS datasets variables attributes. (Type, length, name, label, format and informat).

  1. Type: character and numeric data is the type of the variable.
  2. length: The length of variable means the how many character or digits that variables take to store the value.
  3. Name: the name of the variables
  4. format: The way in which we want to store the variable.

Ex: ddmmyy10. is the date format

  1. Informat: the variable which already in some standard SAS format and we want to convert it

into some other format it is informant.

Ex: suppose, if we want to convert 10,300 as $10,300 in SAS

Then here we will use the dollar8. Informant

7) what is the use of libname statement in SAS?

Ans: libname statement is use for the assigns the path of file which are store in some folder.by using that path we can access that files.

Syntax: libname file_ref “ path of the folder”;

8) what is the difference between proc means and proc summary?

Ans: The use of the both procedure is to make the descriptive statistics of the data and the proc summary with the print option is an identical to the proc means.

Syntax:

Proc means data = dataset_name;

 Var variable names;

Run;

Proc summary data =dataset_name print;

 Var variable_name;

Run;

9) How many different ways to create the macros in SAS?

Ans: we will create the macro for reducing the programme which reduce the time for executing it.

There are 8 different ways for creating macros in SAS which are as follows,

  1. %let statement
  2. %macro statement
  3. %global statement
  4. %local statement
  5. %windows statement
  6. %input statement
  7. into clause in proc sql
  8. using call symput routine

10) what is the use of proc report in clinical research process?

Ans: Proc report is the procedure in SAS for creating the tables that show some information regarding the study results.

Suppose in clinical trials many times we want to create shift table which show the how much shift occur form baseline to post treatment. For summarizing that results we want to create the mock up table. In SAS using Proc report procedure we will create this mock up tables.

Syntax:

Proc report data= Dataset_name;

 Column variable_names;

 Define variable_name / attributes options;

Run;

Author: Mayur Kharche (Cinical SAS programmer & Biostatistician)

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