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****MATHEMATICS STATISTICS QUIZ-3**

**MATHEMATICS STATISTICS QUIZ-3**

**Dear Readers,**

**As per analysis for previous years, it has been observed that students preparing for JEE MAINS find Mathematics out of all the sections to be complex to handle and the majority of them are not able to comprehend the reason behind it. This problem arises especially because these aspirants appearing for the examination are more inclined to have a keen interest in Mathematics due to their ENGINEERING background.**

**Furthermore, sections such as Mathematics are dominantly based on theories, laws, numerical in comparison to a section of Engineering which is more of fact-based, Physics, and includes substantial explanations. By using the table given below, you easily and directly access to the topics and respective links of MCQs. Moreover, to make learning smooth and efficient, all the questions come with their supportive solutions to make utilization of time even more productive. Students will be covered for all their studies as the topics are available from basics to even the most advanced.**

**Q1.**If the standard deviation of the observation -5,-4,-3-2,-1,0,1,2,3,4,5is √10. The standard deviation of observations 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 will be

Solution

The new observations are obtained by adding 20 to each. Hence, Ïƒ does not change

The new observations are obtained by adding 20 to each. Hence, Ïƒ does not change

**Q2.**The marks of some students were listed out of 75. The SD of marks was found to be 9. Subsequently the marks were raised to a maximum of 100 and variance of new marks was calculated. The new variance is

Solution

**Q3.**Sum of absolute deviations about median is

**Q4. If the mean deviation of number 1,1+d,1+2d,…..,1+100d from their mean is 255, then the d is equal to**

Solution

**Q5.**The mean of 30 given numbers, when it is given that the mean of 10 of them is 12 and the mean of the remaining 20 is 9, is equal to

**Q6.**The mean deviation of the data 2,9,9,3,6,9,4 from the mean is

**Q9.**If the variance of 1,2,3,4,5,…,10 is 99/12, then the standard derivation of 3,6,9,12,…., 30 is

Solution

**Q10.**A data has highest value 120 and lowest value 71. A frequency distribution in descending order with seven classes is to be constructed. The limits of the second classes-interval shall be