Tag: CBSE

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Twinkling Stars

  • Twinkling of stars is due to atmospheric refraction of starlight.
  • The starlight undergoes refraction continuously when it enters the atmosphere.
  • The atmosphere has different media of different refractive index.
  • During refraction the starlight bends towards the normal.
  • Due to refraction by different media the apparent position of the star is different from its actual position.
  • The stars are very distant and they act as point-sized sources of light.
  • The physical conditions of earth’s atmosphere are not stationary.
  • Thus the apparent position of the star fluctuates.
  • The star sometime appears brighter and sometimes later fainter. This is called twinkling effect of a star.
  • Planets are not twinkling because they are much closer to the earth.
Twinkling stars
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Statistics

Topic Tree

  1. Mean
  2. Mode
  3. Median
  4. Graphical interpretation

MEAN

Mean for ungrouped data

Mean for grouped data

  1. Direct method
  2. Assumed mean method
  3. Step-deviation method

Direct method

Mean is given by the following formula by direct method

Assumed mean method

Mean by assumed mean method is given by the formula

where a = assumed mean
di = xi -a

Step deviation method

Means is given by step deviation method as

h = class size

MODE

Mode for grouped data

l = lower limit of the modal class

h = size of class interval

f1 = frequency of modal class

f0 = frequency of the preceding modal class

f2 = frequency of the succeding modal class

Modal class = class corresponding to the maximum class frequency.

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Doubt Clarification for CBSE Students

Hi guys!

Greetings! A good news to all Saitechies. Never worry about your poor performance in your school tests and examinations. Stop worrying! Draw out an action plan. Know your objectives. You are studying for your sake. You are the problem, and you are the solution. Success and failures are the crests and trough of a progressive wave. If you are always successful, something is wrong! You cannot be always wrong. Discuss with your parents. Approach a mentor who knows about your family and yourself at least for a few years.

Never follow your friend or website or social media blindly. Study carefully about your failures. This is called failure mode analysis. Draw a cause and effect diagram.

Know your strength and weakness. It is called SWOT analysis.

Budget your time and effort. We are here to help you. Follow the steps given below carefully.

  1. Let us assume you marks scored x Rs. 1000 = Your Dad’s or Mom’s salary.
  2. Your parents have invested their earnings in your education.
  3. Let us assume their expectation is 100. i.e. Rs. 10,000 VFM from you (Value for money invested in your education)
  4. What you have scored may be around 40% i.e., you have earned Rs. 4,000 in a particular subject. It means you have wasted Rs. 6,000 of your dad’s or mom’s investment in one subject.
  5. Most of the students are not bothered about the percentage failure. They are simply content with their passed out marks. Just think about that, if you have the missed out question been asked in the final examination.
  6. Follow this strategy. Target some lessons or concepts and score 100% in the selected topics. Claim yourself 100% if you have scored full marks in all attempted questions. You may have not attempted some questions and scored only 60%. However, you should note down one secret is that you have scored 100% in the 60% preparation of your examination. Are you happy? Yet, you should not stop with that.
  7. Target 40% failed questions. This is the money Rs. 4,000 you have lost. It should be collected at any cost. We are ready to give you the marks you have lost in your school.
  8. Write to us or enter your lost marks in this online form. All your data are kept confidential. Saitech SMEs will help you to solve your issues. They will guide you suitably and conduct re-exam. Use Lifetime Saitech Study Notes and perform well in the re-exam.
  9. If you have any specific doubt in any particular concept in any basic subjects you may enter your doubts in our online doubt register get them clarified.

All the Best Students!

Our Advance Wishes for your Successful Examinations!!

Academic Mentor

Saitechinfo