# Questions tagged [test-for-trend]

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### Nonparametric test for difference in trends?

I have an experiment where two groups of individuals get some variable repeatedly measured at regular intervals. I'd like to know if one group is trending faster or slower than the other (and in what ...
243 views

### Trend prediction with binary data

I have data of 11 years where for each year the values are binary (0 and 1). The sample sizes for each year are different (for example for 1989 n=8 and for 2004 n=30). The goal is to see if there is a ...
17 views

### Which test to determine if there is a difference between pharmacological reaction and population characteristic (e.g. ethnicity) in R?

I have a data set where each row represents an individual and their respective measure of pharmacological reaction (protein level) in addition to their epidemiologic characteristics (e.g. ethnicity, ...
1k views

### Back-transforming contrast lstrends results in r

I calculated a linear mixed model using the packages lme4 and lsmeans with the lmer-function, where i have one dependent variable rv and the interacting factors treatment, time, age and race. I'm ...
2k views

### Is there an accepted definition for “P for trend” or “P-trend” [duplicate]

So is "P for trend" the same in principle as a common-or-garden P-value, but in a specific application i.e. odds ratios? And can P-value, P for trend, and P-trend be regarded as interchangeable ...
523 views

### Is there a nonparametric test available in R to test for a trend in a binary variable?

I have e.g. the following (n=14) time series data: 0,0,0,1,0,1,0,1,1,0,1,1,1,0 By looking at this time series, it is easy to see that in the first half we have more zeros than ones and in the second ...
1k views

### Would including “year” as a categorical random effect remove a long-term trend in a mixed effects model?

I am trying to detect evidence of warming in a monthly temperature time series over a 20-year period by testing for a trend. I have precisely followed the method of Crawley (2013) The R Book, 2nd ...
549 views

### Huge discrepancy between analytic Mann-Kendall statistic and its block bootstrap estimate

I am analyzing some environmental time series and I use Mann-Kendall test to check for monotonic trends. However, I am a little bit concerned about autocorrelations in my data, since standard Mann-...
5k views

### Interpretation of Mann-Kendall statistics

I am doing a trend analysis for vegetation dynamics using Mann-Kendall test for trend detection and Sen's slope for computing the magnitude of the trend. There are 6 sites inside a conservation area ...
2k views

### Mann-Kendall test in R using 'Kendall' package: exact test or approximation?

Problem: I am trying to perform a test for trend using the MannKendall() function available in the Kendall R package. My number of data points is n=11. For this ...
44 views

### Statistical test to assess the strength of the assertion “time series' values stayed the same” [duplicate]

The title somewhat gave my question away, but here goes... I have a time series of values covering a certain time span... If I chart it, I can visually conclude values roughly stayed the same. That ...
170 views

### Given sales data for a product, what is the best way to calculate the trend period for it?

I am looking for a statistical way to calculate an approximate in-trend period for a product from its sales data over a time period. Of course, in the 'in-trend' period, the sales of the product ...
1k views

### Detect unusual trends and anomalies using mixed data (categorical and numerical)

I've been asked to detect "unusual trends and anomalies" using data similar to ATM transaction data. Each entry has a mixture of numerical and categorical variables, things like transaction ID, ...
82 views

### unit root tests: trend included for bounded series

X lies in a 0,100 interval and i want to check if X has a unit root. In (A)DF, and PP unit root tests one can have an intercept and/or a trend (in addition to the level and difference X lags). But ...
90 views

### Which trend test should I use?

Sorry if this is a newbie question. For example, I have 5 groups and each group has different amount of people, and I got the face recognition score (in percentage, between 0 and 1) for all people in ...
429 views

### Are my data values too small for chi-squared for trend? If so what trend test can I do instead?

I'm doing a project about dilated kidneys, these can be arranged into mild, moderate and severe. There are 53 patients in total. I want to see if there is a trend in the severity of dilatation between ...
159 views

### Analysing a genotypic 2X2 table instead of a 3X2 table

This could be a simple question to seasoned statistical genetics folks. I have delved into this doing an analysis for a friend on the sideline of a bioinformatics task I was helping her with. An ...
783 views

### How to determine trend in rainfall data?

I have annual average rainfall data in mm/day units. I want to see the trend of the rainfall, whether its increasing or decreasing. How to do this. My teacher told to put a linear regression line and ...
955 views

### How to deal with different numbers of days in a month for comparison?

My question is very basic, and I'm looking for a conceptual answer. We put about 55000 values (individual deliveries) on a graph. They are sorted by day of the month to see if there's a trend and to ...
77 views

### Time series Analysis using LS

I know this is a bit of a broad question but generally if I have a time series and I want to measure whether it has trend according to time I do the following: I regress the series against time, time^...
304 views

### Trend analysis for change in multivariate distribution over time

At each time point, I have a multivariate distribution $x=[x_1,x_2,x_3]$. I don't have that many time points around 3-15. I would like to know whether the change of the distribution over the time is ...
4k views

### Trend Analysis: How to tell random fluctuations from actual changes in trends?

I hope somebody in here can help me: I'm looking for some pointers as to how to distinguish random fluctuation from actual changes in trends, e.g.: In a time series with measures taken at monthly (...
3k views

### How to perform a test for trend on an ordinal variable in logistic regression?

I have a dichotomous outcome (gallstones/no gallstones) and an ordinal predictor variable consisting of four classes (body mass index <25(ref.), 25-30, 30-35, 35-45). I want to perform a test for ...
76 views

### Can you compare groups over time if data has been collected at different time points?

If have two groups with follow-up measures of a normally-distributed continues outcome measure. One group is measured at 4 time points with unequal intervals. The other group is measured at 7 time ...
289 views

### mixed results for stationarity tests and structural breaks

Following situation: I want to forecast a time series of the number of trucks on the motorway in some country. Here how the regular week looks like: I have data for 4 years and divide the huge time ...
758 views

### Equivalence of p-values from Jonckheere-Terpstra test and Kendall's tau

I'm using the Jonckheere-Terpstra test to confirm whether an interval variable, distributed across five levels of an ordinal variable, display a significant trend. I'm using the clinfun package, ...
43 views

### Is there a method to disentangle multiple lines of data that are intermingled?

I have 3 temperature sensors that record data once a minute. All 3 temperatures have the tuple value (instant, temperature). The problem is, they may come in a random order and thus there's no way to ...
546 views

### What is a “Wald test for trend?”

I am reviewing a manuscript and the authors state that some results are by a "Wald test for trend". Has anyone heard of this? I hadn't, and Google revealed nothing. I know I always say to provide ...