Covariance vs. Correlation

Covariance and correlation are two statistical concepts that are closely related, both conceptually and by their name. The excerpts below are from a concise article that differentiates them.

Difference Between Covariance and Correlation

“Correlation is a special case of covariance which can be obtained when the data is standardised. Now, when it comes to making a choice, which is a better measure of the relationship between two variables, correlation is preferred over covariance, because it remains unaffected by the change in location and scale, and can also be used to make a comparison between two pairs of variables.”

Key Differences Between Covariance and Correlation

“The following points are noteworthy so far as the difference between covariance and correlation is concerned:

  1. “A measure used to indicate the extent to which two random variables change in tandem is known as covariance. A measure used to represent how strongly two random variables are related known as correlation.
  2. “Covariance is nothing but a measure of correlation. On the contrary, correlation refers to the scaled form of covariance.
  3. “The value of correlation takes place between -1 and +1. Conversely, the value of covariance lies between -∞ and +∞.
  4. “Covariance is affected by the change in scale, i.e. if all the value of one variable is multiplied by a constant and all the value of another variable are multiplied, by a similar or different constant, then the covariance is changed. As against this, correlation is not influenced by the change in scale.
  5. “Correlation is dimensionless, i.e. it is a unit-free measure of the relationship between variables. Unlike covariance, where the value is obtained by the product of the units of the two variables.”


Difference Between Covariance and Correlation by Surbhi S

Importance of Stupidity in Science

The Importance of Stupidity in Scientific Research

“Science makes me feel stupid too. It’s just that I’ve gotten used to it. So used to it, in fact, that I actively seek out new opportunities to feel stupid. I wouldn’t know what to do without that feeling. I even think it’s supposed to be this way.”

The more comfortable we become with being stupid, the deeper we will wade into the unknown and the more likely we are to make big discoveries.

“Productive stupidity means being ignorant by choice. Focusing on important questions puts us in the awkward position of being ignorant. One of the beautiful things about science is that it allows us to bumble along, getting it wrong time after time, and feel perfectly fine as long as we learn something each time. No doubt, this can be difficult for students who are accustomed to getting the answers right. No doubt, reasonable levels of confidence and emotional resilience help, but I think scientific education might do more to ease what is a very big transition: from learning what other people once discovered to making your own discoveries. The more comfortable we become with being stupid, the deeper we will wade into the unknown and the more likely we are to make big discoveries.”


The Journal of Cell Science: The Importance of Stupidity in Scientific Research

MD/PhD/JD Combined

“Hello fellow pre-medical students. Let me introduce myself…I am currently a junior pre-medical student at Harvard University. Thus far I have maintained a stellar academic record of a 4.0 grade point average with a triple major in Quantum Mechanics, Biophysics, and Neuroanatomy. In addition, I have helped with the publication of several major articles in the advanced field of Neuroanatophysiopathology in collaboration with Harvard Medical School. I also have an outstanding MCAT score that I believe makes me a superior application. I received a 45T when I took the exam in May of this year.

“Therefore, here is my question. In today’s demanding medical market, I feel that a simple MD is inadequate for a fully-trained medical professional. I feel with the advances in research that are continually coming out, at least an MD/PhD degree should be obtained. However, I still feel this would be an inferior education to someone such as myself. I am adamant that a JD would fully complement the MD/PhD education so the fully-trained medical professional could be competitive in the field of medical law and in order to better protect his or her assets in case there ever arises any type of litigation.

“Consequently, I am looking for advice from similarly superior applications such as myself. Please, only people with a 4.0 GPA from a superior Ivy League institution and at least a 41 MCAT score. Advice from anyone else would be advice from an inferior applicant and therefore futile.

“So, superior applicants: What is the best way to obtain a combined MD/PhD/JD degree?

“Thank you. And please, no trolls, this is a serious question.”



Student Doctor Network: MD/PhD/JD Combined

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