pvalue

  1. F

    Constructing intervals VS hypothesis testing?

    Hi folks, let me briefly anticipate that I am a total newby to the magical world of statistics. So, right now I'm preparing for a "quantitative methods for economics" test, but while doing my exercises I found myself wondering about what could be very stupid things. here's the thing: I had...
  2. E

    Multiple testing correction - What constitutes a test?

    Hello! I am not how to tackle my experimental setup in terms of multiple testing correction: I have three performance measures (m1,m2,m3) that I collected from 20 individuals. On top of that I have two measures of some anatomical feature. I correlated every anatomical feature with all the...
  3. A

    p values, alpha, and errors

    I was speaking with a classmate about subject heading for this thread and it made me a bit confused. Here are my thoughts: the way I explain p value: probability of observing effect when, in reality, there is no effect. This translates to probability of data given the null (null=there is no...
  4. M

    Small difference but still significant?

    I hae sample size of 67 participants. They took a pre and post knowledge survey. The maximum score was 14 answers correct. I run a pair ttest. These are my results: pre 9.3 SD 2.077207 post 9.8 SD 2.157419 p value; <0.05 I have to present this to a non technical audience. My...
  5. C

    What test to get a P-Value?

    So I have a group of students all divided by different categories in response to a poll. There is a total of 34 students. Depending on each answer, I assigned the student a 1, 2, 3, or 4 for that category. For example, favorite candy 1 = twix 2 = snickers 3 = gum 4 = none. Now that I've divided...
  6. C

    average p values???

    I have to compare demographics of a study that was s . In the "pre" group, I have 385 patients, in the post group, I have 317 patients. No patients are the same; I also took all of their ethnicities and compiled it into my MS excel spread via 0, 1, 2, 3...
  7. C

    can you do a chi sq w/ 2 different n sizes?

    can you do a chi sq w/ 2 different n sizes? I have an experiment with 2 groups (pre medicine and post medicine). Group 1: 400 subjects Group 2: 332. When Put the data in (via 1 and 0s) into my SPSS I keep getting really weird answers. How can I accommodate for the 68 subject difference...
  8. C

    T test vs. Chi Sq

    Is an unpaired t-test the same as a chi sq test with respect to the resulting p-value if I'm using categorical data (0s and 1s)? Thanks.
  9. C

    3 Arm Study: Categorical Data needs a P-Value!

    Hi, I conducted a 3 arm study and now I am trying to find signficance/lack of signififance. Some data I gathered, such as age was easy to calculate via ANOVA tests. But now I have smoe categorical data that neds to be analyzed. For example, I examined the quality of my procedure and it was...
  10. C

    3 columns of categorical data - what test to use for significance?

    Hi I did surveys on pre-teens, teens, 20s (3 "columns") and need to find signfifiance (p-value). What test do I use? I keep trying Chi square on graphpad prism 5, but I keep getting the message Analysis of Contingency Table: Overview Chi-square calculations are only valid when all expected...
  11. C

    Which statistical test to use for significance (p-value)?

    Hi, I am trying to find significance in a study I conducted. There are 3 groups (so 3 columns on MS Excel) and I am testing significance between them. I am testing for significance between male and female (so I inputted 0 = male, 1 = female). How do I test for significance? I use statistical...
  12. M

    how to exclude block effect (I think)

    Hi, I have done a simple experiment, with one control group and one treated group. Each group have between 3-5 replicates. The whole experiment is repeated three times. If i do a normal student t.test for each experiment i get a significant difference, however if I do a student t.test...