help me!

  1. C

    Basic Stat

    Help. I got stuck in my stat reviewer, kindly help me. (Google can not help me as i do not understand its discussion) 1. A vaccine that is currently used to immunize people against a certain infection has an 80% success rate.That is, 80% of individuals who receive this vaccine will develop...
  2. A

    Comparing groups- what test to use

    Hello, I am looking to compare the means for two groups (midfield - forward; top - bottom) against each other. Could someone please assist me in choosing what t test to use, or whether it is even a t test. an example of the data I am comparing is: Goals Top 5 Goals Bottom 5...
  3. A

    What statistical test do i need to run?

    Hi there folks, I'm having a little difficulty choosing what statistical test i need to run, I've conducted a series of behavioural experiments, that involves three different groups; yet all have the same individuals. The trials are based around recording behaviour both before and after the...
  4. B

    Hypothesis Test Help!

    Here is what I have thus far. My teacher has a theory that 40% of students at the university are female. I needed to survey 30 random students and asked them if they think 40% of students are female. 22 said yes while 8 said no. I need to carry out a hypothesis test to claim his...
  5. M

    Little litle help with Stata! I'm a beginner!

    Hi everybody! I'm using stata since 3 weeks ago and i'm having problems doing a project for my university! I have to analyse political participation of immigrants in France and United Kingdom. From european social survey I got some variables which i would like to use such as "donated...
  6. L

    Struggling to select right stats test.

    Hi there folks, I'm fairly new to science, love the learning, daunted by the statistics. I've recently finished a summer-long experiment in the lab, and am trying to write it up, but every time I think I've picked the right statistical analysis to run on the data I get cold feet and become...
  7. S

    Does my research proposal make sense? [Basic Stats]

    Hi everyone, I'm new to statistics, statistical packages and research methods in general. Yet I'm fascinated by the subject and want to learn as much as possible. I would love to have inputs by you experts on my project proposal and the analysis I have in mind. The research purpose of my...
  8. C

    Stata 11.0 - Type mismatch r(109) byte to strin variable

    Hello there, I just started working with Stata (Version 11.0). The search in the FAQ and on other pages showed no results so I am trying it here. I have a variable lit (float %21.0g) with the values "Yes, literate" and "No, illiterate". My aim is to create a literacy dummy to work with...
  9. H

    Re: Help needed for forecasting model

    Hi, I have a dataset of some monthly usage values. I have to forecast the for the next 12 months. I have taken log of data for ease of use. It seems to me that ARMA(2,0,2) model fits best for it. Can you confirm if I am right or wrong? If it is, please tell me which one fits the best. Also...
  10. J

    Manual Forward Selection - order of covariates

    Hi all, I have a conceptual model, with different covariates to explain an o=e relationship. I have confounders and effect modifiers. I am unsure, to begin the manual forward selection (for which I will only add variables based on certain criteria), with covariates CLOSER to the main...
  11. L

    iteration using a loop in R

    Hi, I have two vectors as follows: popd = vector(mode='numeric', 100) popr = vector(mode='numeric', 100) These represent the initial distribution within 2 populations. I want to define these e.g. popd[]=0.01 popr[]=0.01 These populations will then transform according to the following...
  12. S

    Method of Moments

    Question: Let X1, X2, ... , Xn be a random sample of size n from a population with pdf f(x;theta) = [3(theta - x)^2] / (theta)^3 from 0 < x < theta and zero otherwise. Use the Method of Moments to find a point estimator for theta.
  13. S

    Comparing Likert scales of different lengths

    Hi there talkstats experts. For my thesis I am doing research about listener's attitudes towards 4 different Dutch accents. Next to that I also do research about the lengths of Likert scales. I did 2 surveys with the same questions but one with a likert scale length of 6 and one of 7 answer...
  14. J

    Hypothesis Testing

    Hi all, I've got an MCQ question for uni that I'm not sure how to go about :confused:. If anyone could point me in the right direction that would be fantastic. "A university administrator believes that less than 40% of full-time staff regularly use public transport to travel to the...
  15. S

    Mediation with Structural Equation Modeling....

    First...Hello! My question is about how to test mediation with structural equation modeling. I know there is a way to test mediation with regression using a stage successive approach, but some people say it is very better to do mediation using structural equation modeling. Suppose I say...
  16. J

    Test selection help for multivariate response and predictors

    I need help determining what method would be applicable to the following situation. There are 2 chemicals, A and B. Also, there are two organisms, say Jim and Kelly. It is impossible to separate Jim and Kelly. Although, sometimes, levels of Jims or Kellys might be slightly more than the...
  17. S

    Structural Equation Modelling....The simplest explanation you can give....

    Ever since last year that i started my research SEM has proved to be a daunting task. Reading a lot of books and articles....I still have some simple questions that I like answers for....Being familiar with other regression analyses, SEM has tested my limits to stats and I am finally here to ask...
  18. G

    No clue when to use nCr or multiply the probabilites..

    I'm completely baffled as to when to use nCr or multiply the probabilites.. Here's an example.. Jane buys 5 jam donuts, 4 cream donuts and 3 plain donuts. Calculate the probabilities of the following events. A)All 3 donuts eaten contain jam.. B) the 3 donuts are of different kind. Why wouldn't...
  19. E

    Help! my model isn't predicting any yes outcomes and don't know why

    I am producing a logistical regression analysis to find a model to predict whether someone has minor mental health problems or not. I'm almost certain i've coded all my data correctly but no matter which variable I put into the model it doesn't predict any yes outcomes. my classification table...
  20. J

    I need help with Null Hypothesis type 1 and 2 errors

    Explain which type of error, type 1 or type 2, could be made in each of the following cases. Just pick A, B C or D. For example for (I) Pick one of the four options (A B C or D). For (II) Pick one of the four options (A B C or D) for (III) Pick one of the four options (A B C or D), for (IV) Pick...