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 Question: both variance and standard deviation exactly mean the same thing " it tells how much is the value deviated from mean value " but what exactly is the difference between them By: pradeep madhava     Date: 2012-07-18 Answer: Hi Pradeep, Yes both are the measure of spread around the mean. However, their units are different. Unit of variance is the square of the unit of the data whereas the unit of standard deviation is same as that of data. The mean is also having the same unit that of data. This is sometime helpful when you are looking for the deviation from the mean. We also calculate coefficient of variation (CV), which is the ratio of standard deviation and mean. This is dimensionless as standard deviation and mean are having the same unit. Being dimensionless, we can easily compare CVs for two different datasets. Hope this helps your query. By: Dr. Rajib Maity     Date: 2012-07-20

 Question: what does the moment, physically mean to represent in this probability distribution By: pradeep madhava     Date: 2012-08-11 Answer: There is an analogy between moment in physics and moment in probability theory. Moment in physics is a representation of the distribution of any physical quantity with respect to an axis. Similarly, moment in probability theory is the distribution of the data points or â€˜probability massâ€™ with respect to some point (location). As we know that mean is located at the centroid (â€˜centre of gravityâ€™ while making an analogy with physics) of the probability distribution, the first moment with respect to the mean is zero. First moment with respect to the origin expresses the location of the mean, i.e. distance of the centroid from the origin. Higher order moments are generally expressed with respect to the mean as they have some meaningful representation of the nature of the distribution. For instance, second moment with respect to the mean expresses the spread of the distribution function about the mean. This is used as variance. Similarly third and fourth moment with respect to the me By: Dr. Rajib Maity     Date: 2012-08-21

 Question: what is the physically meaning of mean square value in probability By: pradeep madhava     Date: 2012-09-15 Answer: Did you mean 'Mean Square Error (MSE)' or 'Root Mean Square Error (RMSE)'? These are the measures of difference between estimated values and its true values. Lower the values of MSE or RMSE better the estimated values. By: Dr. Rajib Maity     Date: 2012-09-21

 Question: Dear Sir, I want to learn the basics of probability theory and methods from basic probability to markov chains practically!So I need to know whether any books are available with matlab demonstrations for probability and random process??I need to visualize things practically? By: ManojNiranjan.P     Date: 2012-09-18 Answer: Yes there are many books. Some of them are listed in the reference list of the course. However, all of them may not have the corresponding MATLAB demonstration. You may send your queries to me. If I know the MATLAB command, I will help you. By: Dr. Rajib Maity     Date: 2012-09-21

 Question: sir does Probability Based Civil Engineering Design and Reliability Based Civil Engineering Design is same thing By: Kumar Gaurav     Date: 2012-11-28 Answer: Concept of reliability is based on the probability theory. Reliability based design aims to minimize the probability of failure. Thus, reliability based design methods are more specific compare to general probability methods; however, based on the theory of probability. By: Dr. Rajib Maity     Date: 2012-12-08

 Question: Sir link of assignment is not working By: Kumar Gaurav     Date: 2012-11-28 Answer: Please contact through email sushanta_cet@yahoo.co.in He may guide you or tell whom to contact By: Dr. Rajib Maity     Date: 2012-12-08

 Question: Sir this in connection to my previous question ,as you have mentioned in your reply "reliability based design methods are more specific compare to general probability methods"......sir can u give me some examples of general probability methods? By: Kumar Gaurav     Date: 2012-12-18 Answer: Examples on general probability methods are included in the course material. Please refer to the solved problems. By: Dr. Rajib Maity     Date: 2012-12-21

 Question: sir i have a question. while designing a simple beam by reliabilty analysis, it needs sd and varience for data like loads, cross sectional areas (b and D), Length, fy, fck etc. adding that suppose we need 100 sample,shall i carry out experimental work for 100 times..! Thanks G.ELANGOVAN By: G Elangovan     Date: 2013-03-20 Answer: Dear Elangovan, I doubt whether I understood the context of your query. In the lecture, it was discussed in a general context. The problem of uncertainty in estimating the loads and other factors needs a probabilistic representation. This is generally represented separately for different attributes, i.e., applied load, material properties, uncertainties in construction etc. By: Dr. Rajib Maity     Date: 2013-03-23
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