1. M

    Standard Deviation of a Sequence of Standard Deviations

    Hi, My goal is to estimate arrival times of buses at bus stops where historical GPS data for each bus is available and real-time bus location is available for each bus. What I would like to do is use the historical data to determine the mean time (in seconds) and SD taken for a bus to travel...
  2. A

    Combining two ORs with the same control group

    Hi everybody. I am doing a meta-analysis of observational studies. As the disease I am working on has different stages, some of the studies reported ORs(95%CI) for each stage separately in comparison to a single (shared) control population. I wonder if we can combine these two ORs (and their...
  3. K

    Combining Symmetrized Percent Change (SPC) values

    Hello Talk Stats members, I'm relatively new to statistics, so please let me know if I'm off course! I was wondering if a total symmetrized percent change (SPC) could be calculated from two separate SPC values using weighting as can be done for percent change values. e.g....Total SPC in...
  4. M

    Combining samples for EFA

    Hello, I have conducted an experiment in two different countries. The experiment included a survey. The same survey was used. Is it valid to combine the two sets to perform exploratory factor analysis, or there will be a scale effect (e.g. as in the case of logit choice models). Thank you
  5. B

    Combining Bernoulli distributions

    Combining Bernoulli distributions [Solved] I'm looking for a way to find the standard deviation of a certain distribution. This distribution is created by performing n_0 Bernoulli trials with probability p_0. The number of successes is recorded as n_1. n_1 Bernoulli trials are then performed...
  6. J

    What statistics to use to find a possible correlation of coinciding null results?

    I would like your advice on the following problem: I am investigating the following data: For 600 trials data was gathered simultaneously from two sources (locations in rats brain). Each trial was investigated and either a result was found (some time stamp) or no result was found (a "zero...
  7. N

    Need Help Combining 6 Graphs into One

    Hello, I am an undergraduate student in biology. I have not yet completed a statistics course but I do have basic familiarity with graphing in excel. Here is the problem: We did an experiment in lab and we are supposed to write up a lab report which includes graph. We are given the...