Search results

  1. B

    How to develop a health coverage plan for a particular disease?

    Currently, there is no government health coverage for cancer in our country and the prevalence of this disease is increasing rapidly. So I have collected data on the cancer scenario of the country and want to conduct an academic research where I want to estimate how much money the government can...
  2. B

    How to obtain an unbiased post-stratified estimator for survival probabilities?

    Suppose I have estimated the survival probabilities $\hat{S(t)}_1, \hat{S(t)}_2, \ldots, \hat{S(t)}_H$ from $H$ strata. Now I want to get an unbiased estimate of population survival probability $S(t)$ using these stratum-specific estimates. Then what should be the estimator? Should it be...
  3. B

    Finding MLE by factor analyzing the correlation matrix

    In the book "Applied Multivariate Statistical Analysis" written by Johnson and Wichern, they have mentioned that the MLEs ($\hat{L_z}$) are obtained from the the correlation matrix $R$ by inserting $R$ in place of $[(n-1)/n] \times S$ (where $S$ is the sample covariance matrix) in the...
  4. B

    Understanding the “computationally convenient uniqueness condition” of factor model

    In the book "Applied Multivariate Statistical Analysis" written by Johnson and Wichern, they have mentioned about a computationally convenient uniqueness condition $L^T\psi^{-1}L=\Delta$, where $\Delta$ is a diagonal matrix. Here, $L$ is the factor loadings matrix and $\psi$ is vector of...
  5. B

    Conditional probability of an event given two independent events

    I am dealing with an interesting probability problem. I had 16 subjects randomly divided into 4 different rooms, each room having 4 seats. The subjects were given a question to solve. We knew from our prior experience that only 50% people could solve the problem. In our study, 7 of the 16 people...
  6. B

    Could you please suggest a newbie about publishing Statistics related papers?

    Hello, I am quite new in writing and publishing papers. I have written a few papers, not that tough ones statistically, may be, but well written with properly performed analysis. One paper is on nutritional aspect of the country using a nationally representative data. There I have used a...
  7. B

    Analysis of a longitudinal study where interventions are received at different times

    I have a data set of university students. The university has 8 different assisting programs, mostly like scholarships, for needy students to help them concentrate on their studies. Since it costs a lot of money for the university to run these programs, it opts to evaluate how effective each of...
  8. B

    A regression problem with optional treatment

    I have an interesting problem here and really need your suggestion to analyze the data in a proper way. In 2012 we collected data about retention of the students from first semester to second semester along with some other variables. The retention variable is a binary type variable-...
  9. B

    Simulating correlated lifetimes at pre-specified correlation level

    I am trying to simulate remission times for 100 patients from an exponential distribution with mean 1 year. I also want to simulate after-remission times for these 100 patients. But it is very much likely in the real life scenario that those who remit quickly are likely to have comparatively...
  10. B

    Can I use relative/normalized sampling weights in SPSS?

    Dear all, Can I use relative/normalized sampling weights in SPSS to get the correct standard errors? I have seen that it uses Taylor's linearization method for variance approximation. But I am not sure if the internal formula changes when I want to use relative weights instead of the raw...
  11. B

    How to analyze data with more than one associated categorical dependent variables?

    I have some dependent variables related to the growth of a company having categories like (e.g. for variables indicating net profit, financial turnover etc.) (1) decreasing, (2) stable, (3) increasing and (4) rapidly increasing. Now these variables are associated and ordinal in...
  12. B

    Regression with some associated ordinal dependent variables

    I have some associated categorical dependent variables that are ordinal in nature (with 4 or 5 categories). If I want to see the effect of a set of independent variables (which can be both continuous and categorical) what is the right way to perform the regression? Should that be a...
  13. B

    How should I define missing values due to skip questions in SPSS?

    I have a questionnaire that contains some skip questions. Like, say, the 3rd question is a yes/no type question. Only those who answered "yes" to the 3rd question are requested to answer the 4th, 5th and 6th question and those who answered "no" are requested to skip these three questions. I...
  14. B

    Probability calculation problem for a ranked set sample

    Let us consider a case where a ranked set sampling scheme from $n^2$ subjects has been adopted. There are a total of $n$ RSS blocks. So each RSS block contains $n$ subjects. We will follow up them. Some of these subjects will fulfill a certain criterion and get a treatment and some will not be...
  15. B

    Relationship between sample mean and sample survival probability

    I am not sure if this question is very naive, but I was wondering if there is a relationship between sample mean and sample survival probability. For an exponential distribution with mean mu, S(t)=1-exp(-t/mu}) Now if I generate data from an exponential distribution, can the sample mean...
  16. B

    Simulation of remission and after remission times under specific conditions

    This is basically a data generation problem. Say, t is an exponential lifetime with mean two years. tr is the remission time and ts is the after remission time. So, t=tr+ts. I need to simulate these quantities for 100 patients. Now in real life, usually when tr is smaller, that is when the...
  17. B

    Hot deck imputation issues

    Background: I had a data set containing 212 observations with a lots of missing values. Most of the IVs and DVs are categorical (DVs are ordinal) in nature. There are 3 DVs and about 30 IVs. My intention was to run an ordinal logistic regression. A list-wise deletion keeps only 42...
  18. B

    Does SPSS give standardized factor scores?

    From the Johnson's book, I can see the orthogonal factor model is as follows: X−μ=LF+ϵ So if I use SPSS for extracting factor scores from a factor analysis of several variables, then am I going to get factor scores for mean subtracted variables? Actually my intention is to use the factor...
  19. B

    How to program a Ranked Set Sampling in R?

    I am trying to program a ranked set sampling using R. There are 2*n^2 items and I want to randomly divide them into two equal sized groups with n^2 items in each group. Then I want to use a Ranked Set Sampling from each of these groups to form n RSS blocks with n items in each RSS block. What...
  20. B

    An interesting probability calculation problem

    Hello all! I'll be really glad if you respond to this question. I am working with an interesting probability calculation problem. In my problem there are ratings for 32 chess players. They are divided into two groups to form two chess teams in such a way that each team contains all types of...