trend analysis

  1. Q

    Mann-Kendall interpretation. Working in R, "object 'y' not found"

    I am trying to run a Mann-Kendall over a group of files, to perform the MK on each one. This is precip data, for each area, over decades. I read the data into R, then create df "datalist". I bind all the files into one, and then split them by the name in the first column ("V1"). This all works...
  2. A

    Interpreting a time series trend

    I'm trying to identify a trend in some monthly precipitation time series data (2000-2020). The data are non-normal so I'm running a Mann Kendall test and a Sen's slope test to find the significance and magnitude of the trend. I've found that the data show a significant positive trend (tau = 0.4...
  3. O

    Repeated measures ANOVA trend analysis is confusing me

    I'm trying to understand how trend analysis works with respect to repeated measures ANOVA, but I'm a bit confused and have some questions. My first question at the bottom of this post is the thing I'm most interested in. I'm using SPSS, but it is unclear what is going on with the outputs and the...
  4. J

    Trend analysis

    In a period of 14 years we collected MRIs on different patients. For all the MRIs I have a variable on which day after diagnosis the MRI was made. I want to know if MRIs were made much faster at the end of the study than at the beginning --> so I want to know if there's a trend. How would one do...
  5. J

    Statistical test for annual crude mortality trend (3 years data=3 data points)

    Help, I have the crude mortality figures for 2015, 2016, 2017 and would like to know if the figure for 2017 is statistically different. The population stayed constant over the time period. Year Deaths Pop Deaths/Pop 2015 2242 3400000 0.000659412 2016 2366...
  6. T

    Normalising Search Data

    Hi Guys, Just want to start by saying great forums, some really useful stuff on here! I'm basically a statistics novice, though i did do a few subjects at uni many moons ago, so forgive me if I ask some stupid questions. And apologies if this isn't in the right area. I'm working on a data...
  7. M

    Trend analysis / regression model with missing data

    Hi, I want to apply a Poisson GLM to count data, analyzing trends. However, there are missing counts (i.e. missing values in the outcome variable) in the dataframe. Is there any recommended method how to deal with this? I know there exists "multiple imputation methods" to fill the gaps in the...
  8. Z

    Trend analysis with non-binary variable

    Hi, I have a data set where I have a number of organs that fall into 5 treatment groups. These treatment groups can be organized based on increasing dose (0, 1, 2, 3, 4), with 0 being my vehicle or placebo control. I have about 10 organs per treatment group. I then have 6 different...
  9. R

    Post hoc test for Trend analysis and other

    Hi all, I'm new to trend analysis and would like to get some advice. My study is about treatment intervention on learning. Between-subject variable is treatment group (treatment1, treatment2, no treatment) and within-subject variable is time (time1, time2, time3). My dependent variable is...
  10. A

    How to run trend correlation of multiple subjects? (Beginner)

    Hi! I have a set of data which looks similar to the below Y1 Y2 Y3......Y20 Branch Sales Profits Sales Profits a x1 z1 x4 z4 b...
  11. C

    Non-parametric test for trend suggestions needed

    Hello, I am conducting trend analysis on rainfall time series using the Mann-Kendall rank correlation coefficient (tau). I would like to also use another non-parametric test to increase the reliability of the results, but I am having trouble finding a suitable test. I don't have a dataset...
  12. M

    planned comparisons - contrast coefficients - trends

    Hello! I’m going to conduct planned comparisons with contrast analysis in ANOVA. In particular I am interested in trend analysis. The problem is that I have n=11 groups and I suppose that my trend is quadratic. What are the contrast coefficients for 11 groups? Is there any universal...
  13. P

    Trend Analysis: Mann Kendall

    I doing trend analysis on rainfall using mann-kendall. I have daily rainfall data for 60 years. My p value is close to 0 which indicates that there is a trend in data. But the slope (sen's slope) is also 0 or in some cases 0.000008. How does one interpret these results? Shouldn't the...
  14. D

    Help analyzing bird migration patterns?

    Hi. I am trying to analyze data I have on bird migration and am stuck on what I need to do. Basically, I have the maximum abundance of birds seen per week for 10 weeks for 4 sites within a location, for 5 different species, and over the course of 5 years. So for one year, the abundance...
  15. I

    How to account for short-term trends in time-series data?

    Hi guys, I would like to find out which of my 10 independent variables (IVs) best accounts for the changes of my dependent variable (DV) at different points of time within the last 50 years. My problem: In order to explain the long-term trend of my DV over the last 50 years, I used multiple...
  16. F

    [R] Difference between regression lines significant?

    Hi, I'm a PhD student researching processes of technology maturation. For this purpose I collected patent data which I want to use to differentiate between 3-6 yet arbitrary maturtiy phases (e.g. technology introduction, growth, maturity, decline). For several different technologies I have...
  17. M

    von Neumann test for trend analysis

    Hi! Recently, I’ve come across von Neumann test for trend detection. I cannot find whether it has any particular assumptions – any info (as well as references) would be greatly appreciated. Cheers mcdomell
  18. J

    Best regression using ANOVA technique: trend comparisons in a 3x5 factorial

    Hello all: I need help using the ANOVA technique to arrive at an appropriate form of a multiple regression equation between the response (disease severity) and the two factors tested (spring rate) and (summer rate) in an field study. The experimental design is a 3 x 5 factorial arranged as a...
  19. W

    Incidence rates - best way to do trend analysis?

    Hi everyone, I have a series of admitted patient data and notifiable diseases data over a time period for 3 different study areas. For each year, I have calculated case counts by: overall, male overall, female overall, then each age grouping (<1, 1-4, 5-9,....85+), as well as each age group...
  20. F

    the difference between non-stationary data and random data?

    what are the the difference between non-stationary data and random data? If we detrend a stationary data and make it non-stationary what will happen, will it be random?