Mathematics and Stastics

 Data Sufficiency in Statistics A sufficient statistic is a statistic that summarizes all of the information in a sample about a chosen parameter. For example, the sample mean, x̄, estimates the population mean, μ. x̄ is a sufficient statistic if it retains all of the information about the population mean that was contained … Read more

 Direction test     Introduction: There are four main directions – East, West, North and South as shown below:         There are four cardinal directions – North-East (N-E), North-West (N-W), South-East (S-E), and South-West (S-W) as shown below:       Key points   At the time of sunrise if a man stands facing the east, his shadow will be towards … Read more

 Average   What is Average? The result obtained by adding several quantities together and then dividing this total by the number of quantities is called Average. The main term of average is equal distribution of a value among all which may distribute persons or things. We obtain the average of a number using formula that … Read more

 Compound Interest   Let Principal = P, Rate = R% per annum, Time = n years.   When interest is compound Annually:    Amount = P 1 + R n 100 When interest is compounded Half-yearly:     Amount = P 1 + (R/2) 2n 100 When interest is compounded Quarterly:     Amount = … Read more

 Data analysis Data analysis is a primary component of data mining and Business Intelligence (BI) and is key to gaining the insight that drives business decisions. Organizations and enterprises analyze data from a multitude of sources using Big Data management solutions and customer experience management solutions that utilize data analysis to transform data … Read more

  HCF & LCM HCF & LCM are acronym for words, Highest common factor and Lowest common multiple respectively. 1. H. C. F While we all know what a multiplication is like 2 * 3 = 6. HCF is just the reverse of multiplication which is known as Factorization. Now factorization is breaking … Read more

 Addition and subtraction in vedic maths Vedic maths Addition Usually if we want to add to numbers say 52 and 66 we would add the unit digits. and if there is any remainder we will bring it to the tens digit and atlast we will add the tens digit. Now we will do … Read more

Variance Variance (σ2) in statistics is a measurement of the spread between numbers in a data set. That is, it measures how far each number in the set is from the mean and therefore from every other number in the set. In investing, the variance of the returns among assets in a portfolio is analyzed … Read more

 Time and distance Relationship between speed, distance and time Speed = Distance / Time or Distance = Speed × Time Average Speed = 2xy / x+y where x km/hr is a speed for certain distance and y km/hr is a speed at for same distance covered. As we know, Speed = Distance/ Time. … Read more

 TIME & DISTANCE In this module we will deal with basic concepts of time and distance, speed, average speed, conversion from km/h to m/s and vice versa. This chapter will form the basis of further concept of relative speed which is used in train and boat problems. Important … Read more