Search results

  1. T

    95% confidence interval using standard error of a proportion

    Hi, I've had a chance to look through your comment and again it's really helpful. Within this test I agree that with 48 successes out of 50 the upper bound is basically 1 however if I had a similar test which has say 38 success out of 50 how do I go about finding the upper bound? Can you...
  2. T

    95% confidence interval using standard error of a proportion

    Thank you so much for this, really appreciate you taking the time to explain it.
  3. T

    Within study calculate statistical significance

    Hi thank you so much for your reply. Not really, now you’ve explained it I agree I don’t think I should be testing for statistical significance. I was just a bit lost as to how to prove if it’s “OK” to just do test A rather than both parts of test B. Would you mind explainIng how I would prove...
  4. T

    Within study calculate statistical significance

    Hi I have a binomial experiment whereby I’m comparing the diagnostic accuracy of Test 1 against Test 2. Test 2 comprises of two parts (A and B), with both parts completed a binomial response is given. Yes there is the disease or No there isn’t a disease. However Test 2 is expensive to complete...
  5. T

    95% confidence interval using standard error of a proportion

    Hi thank you, sorry this is still a bit beyond me can I just check so for calculating Betainv is α = # of successes in n trials and β = # of failures in n trials. Which is straight forward to calculate in excel. So where does this formulae come into play?
  6. T

    95% confidence interval using standard error of a proportion

    Hi thank you so much for getting back to me: I wondered if you could help me with a worked example. I presume you are referring to the following formulae when you suggest using beta distribution confidence interval: From the original information: Alpha = 0.05 K= 49 n=50 Betainv = not sure...
  7. T

    95% confidence interval using standard error of a proportion

    Hi, firstly apologies my stats knowledge is limited. I am looking at linear binomial regression. I have a study that has a yes or no output so binomial. Out of 50 cases I get a yes rate of 49 so a probability of success (p) value of 98%. I want to work out the 95% confidence of this...
  8. T

    Sensitivity and specificity

    Hi firstly wow thank you seem to be quite knowledgeable in this area. So I’m specifically looking at patient post relocation of the knee looking for associated fractures. So I’m doing a retrospective study, so my pool of patients will be all those with a confirmed dislocation on initial x-ray...
  9. T

    Sensitivity and specificity

    Hi ok no problem. At the moment I have no data as this will be empirical research. So my research is on looking for fractures on MRI radiology images. I have test A which is a type of MRI scan that looks at the bones and Test B which is another type of MRI scan looking at fluid i.e blood...
  10. T

    Sensitivity and specificity

    I therefore want to see the sensitivity and specificity of the A or B against the A and B combined which I’m having to assume is giving me the truth.
  11. T

    Sensitivity and specificity

    Hi, I see what you mean, so when I say there isn’t a gold standard that’s not strictly true, there is a gold standard but it’s only possible in autopsy so not available to me as part of a dissertation. Previous studies using autopsy’s sugest the specificity and sensitivity of test A+B combined...
  12. T

    Sensitivity and specificity

    Hi thanks for the reply. Hmm sorry, I'm not sure what you mean by the truth of the test? The A + B tests combined provided the highest level of sensitivity and specificity available and I plan to perform Test A then Test B then Test A + B combined on the same patient.
  13. T

    Sensitivity and specificity

    Hi I have 2 test's A and B which are performed on patients and are done together to give a high level of sensitivity and specificity. However doing both test A and B is expensive. I want to work out the sensitivity and specificity of A individually and B individually to see if there's a...