I am currently working on a research project investigating the use of 3D printed patient specific anatomy in pre-operative planning. The surgeons fill in a questionnaire after the operation. Due to the cost of printing and limited time allocated by the university we only managed to conduct 5 cases. The questionnaires are a combination of Likert scales and subjective questions.

I am really stuck at the moment with figuring out how to appropriately interpret the data. I have spent a lot of time on google but being a medical student with limited to no statistics experience, I have yet to find a solution.

If anyone could make any suggestions/point me in the right direction that would be much appreciated.

Best regards,

Stanley ]]>

A peculiar deck of playing cards is like a regular deck, but has five suits: spades, hearts, diamonds, clubs, and clovers. There are 13 cards in each suit: Ace, 2, 3, …, 10, Jack, Queen, King. There are thus 5×13 = 65 cards in this deck. Consider dealing a 6-card hand from this deck.

A well-suited hand is one that contains at least one card of every suit, no more than one card of any kind (no pairs, etc.), and not all cards of consecutive kinds. An example of a well-suited hand is {2 of spades, 4 of hearts, 5 of diamonds, 8 of clubs, 10 of clubs, Jack of clovers}.

How many different 6-card hands can be dealt from this deck that are well-suited?

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I started off by using 5c1 to choose the one suit that gets a repeat, then multiply by 13c2 for the possible combinations of two cards to choose from that suit after that. I thought at this point that I could do 13^4 for the remaining cards, but then I realized that I have to avoid repeating anything (to avoid pairs). How can I do that? And how do I avoid getting all consecutive cards? ]]>

But what if your entire population is invited to respond to the internet, for a survey? Response rate may be low, as it can be in a random sample, but at what point does this type of survey become a convenience as compared to probabilistic sample?

Is the key how many actually recieve the invitation, how many respond, how many have access to the internet or what? ]]>