1. C

    Confidence intervals with a skewed histogram

    If a histogram is skewed right, does that give us any concern about the validity of a calculated confidence interval?
  2. P

    Reliability, validity, cronbach alpha figures for Method/measures section

    Hi, My research is on people on particular visas in the US, i.e., immigrants and mostly Asians. In my methods section when I write about the measures, where do I get the Reliability, validity, cronbach alpha figures from? Firstly, do I search for previous research on Asians or on...
  3. I

    Newbie needs help: my research sample is one end of the bell curve only

    Hello forum members I did the wonderful Princeton Statistics 1 Coursera MOOC which I really enjoyed. But I have hit a problem with a project which I can't find answers to in my course notes as this introductory course only briefly covered non-parametric statistics. I have a normally...
  4. R

    Generalizability of results / External validity

    Hi everyone, Employment of probability sampling to draw a sample from the population in a quantitative study (cross-sectional design, data collected via surveys) is one of the criteria needed to make inferences to the population. What other criteria are in play? How to determine, where...
  5. W

    accounting for volunteers giving a survey

    When writing about validity/ reliability, how do I take into account volunteers who have given the treatment to the participants rather than myself (the researcher)?
  6. A

    Need assistance to conduct a validation of research instrument

    I'm completing a PhD degree and need help from five PhD holders in order to conduct an instrument validation (face value and content validation). The instrument contains 17 questions which are used to to measure 4 central constructs. The instrument is based on a previously developed and...
  7. 1

    Post Tests on a one-group pre-test/post-test research design

    I have conducted a survey as a pre-test. Is it okay for the post-test to be a semi-opened questionnaire regarding the same content. Will validity be an issue?
  8. D

    Psychometrics with small datasets?

    Hi, I am developing a new measurement scale for cannabis withdrawal, but only have 50 people in my dataset (they filled the scale in every day for 3 weeks - 1 week was a baseline smoking as usual phase, the other two were abstinence from cannabis). I want to do a full psychometric...
  9. D

    Using Generalized Estimating Equations to test item validity on a scale

    Hi, I am creating a new measurement scale for withdrawal from cannabis, and have daily withdrawal data from 50 people for 1 week before abstinence (baseline smoking as usual) and then for 2 weeks of abstinence. There are 26 items on this new scale, and essentially what I want to is to rank...