1. N

    Mann-Whitney U Test test valid for percentage data?

    Is the Mann-Whitney U Test test valid for percentages (there are no discrete counts underlying the percentage)? All my data points are average percent cover of seagrass with about 53% of the data being zeros across 8 group levels/columns (4 years x 2 seasons per year). I'd like to test the null...
  2. N

    z-test or beta regression for assessing differences between groups of averaged proportions?

    If I'd like to test the hypothesis that there is no difference in mean seagrass cover between two months, over all years, what test/analysis is best to use? My thoughts move to a z-test because I'm testing differences between two samples and the sample size is >30. On the other-hand I've...
  3. S

    How to compute the standard error with only sample size, mean of percentage and interquartile range?

    I have a percentage which is the rate of reduction. For example, each patient was measured on a scale several times, and the reduction rate was computed by (time 2-time 1)/time 1, I think. So, the reduction rate measures how much the performance is reduced in the second time. I have two...
  4. R

    How do I find percentage from two values which are coming from two different population sets that has large difference in population sizes?

    I need to find percentage from two values which are coming from two different population sets that has large difference in population sizes. They are also different in nature. I set is teachers and another set is students. I have the performance score of 10 schools. Each schools have filled...
  5. P

    How to interpret Standardized Coeff Beta when DV (in %) is transformed using log feature?

    Hello everyone, I am analyzing the influence of some stores attributes (e.g., quality, price, in-store service, communication ...) on customer loyalty (more precisely share of wallet = how much a customer allocates to a specific store in %: 0-100). I transformed the dependent variables (share...
  6. A

    Statistical test for comparing percentage not mean

    Hi, I am wondering what test should I use to compare two percentage value from two different observations. Let's say I have a damage of crop 15% versus 2% in control, is there a ways to statistically test the significance between the two values? Not sure if this make sense statistically...
  7. S

    Using percentage for 2-way Anova

    Do I have to label my data as percentage in SPSS? I ran a two-way anova, and the p-value was 0.00 but when I did a bar graph, the difference was not significant at all.
  8. C

    Compare Percentages

    I have some survey data and know the number and percentage of "yes" responses. How do I determine if any of the percentage yes regional responses are statistically different from the national yes response percentage. Thank you in anticipation.
  9. W

    Standard Error associated to a variable percentage

    Context: I am a programmer, not a statistician, and I have only some vague ideas of statistical concepts. Also, my english is far from perfect, be patient please. My client needs an estimate of the percentage of taxes he is going to pay, based on what happened in the recent past. He needs...
  10. B

    WTI price vs. Drilling Cost Index

    Hi Folks, I have 2 datasets, each recorded on a monthly basis. The first dataset is the average monthly oil price. The second is a price index for drilling cost. I was to calculate what % change in drilling cost to expect with a 1% change in oil price. The data set spans 8 years and you see a...
  11. T

    Random Odds and Percentage Question

    Hi Everyone, I have a random question related to odds and percentage that I can't figure out. Does this statement in terms of the percentage difference sound true? "The odds for students in group A to graduate are 5.03 (11,734 group A students graduate and 2330 do not) and the odds for...
  12. S

    [R] Prevalence by site. Stuck after fisher.test and pairwise.t.test

    Hi, I run into a problem I can't solve and I got stuck doing the pairwise.t.test. I'll try to give you as many details I could so maybe you can help me out. Thanks in advance. I'm studying the prevalence of one parasite on a host from different localities. I do it by assigning presence...
  13. T

    Senslope as a percentage

    Hi, I found a way to express the nonparametric senslope (which is a median slope joining all pairs of observations) by dividing the senslope by the same data mean value. I have done this for all observations (For example: number of injuries observed per quarter over 6 years). My question...
  14. R

    Percentage Prevalence comparison (non-independent groups)

    Hi all! I have a dataset which I think could potentially be very exciting but I am struggling to find how to analyse it! We have gathered lots of information on the percentage if individuals who exhibit different forms of the same class of behaviour (categorical data- present/absent). All...
  15. J

    Pre/Post Comparison of Percentages, Two Populations

    I would like assistance in selecting tests for two scenarios. I am simplifying a bit here, but basically I want to do a comparison of the percentage of patients who come in for a second appointment, comparing 2011 against 2012. 1) In the "Ideal" case, the two populations are separate. What...
  16. C

    Analysis of Multiple Sites (vegetation) with multiple categories/ranks - HELP!

    I need some advice (and note, I am NOT a stats pro, excel yes, but have only used SPSS and R once) Short story is, I have done a vegetation survey on a gecko tree shelter sites. There are 20 shelter tree sites in each grid. Each shelter tree is I.D. as A(transect line) 0(distance x15m). So A0...
  17. S

    Please help!!

    Hello , I started a Statistics class a few weeks ago and i'm still pretty lost. Could someone explain to me how I should resolve this following problem ? Please. On the math SAT taken in 1994, the average score for men was 500 and the average score for women was 460. The histograms for...
  18. N

    t-test on percentage

    Hi all, Pretty simple question: I have two mean performance scores in percent, one is 70% +/- 3(SEM) and one is 95% +/- 1. Someone said I shouldn't do a t-test to compare these since data can't be normally distributed. Is that true? How would I compare these means then? thanks!
  19. Z

    How to generate a table with weighted values and percentages of the variables used?

    Hi all, I've been looking all over the web for a solution to this but to avail! So, I'm turning to this forum for a solution, if it exists! I want to generate a cross tabulation (between 2 variables) in Stata and have the resulting table to show both the weighted values and the percentages...
  20. J

    Percentage of data points in distribution

    Hello, I have a sample of data for which I have figured out that the population mean for the height of US 12-year-old children is μ = 150 cm with σ = 6 cm. The heights are normally distributed. I now need to figure out the percentage of children have heights between 141 and 159 cm. Any help is...