In general, a trend is an observable pattern in the data.

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6
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3answers
100 views

Statistical test for increasing incidence of a rare event

I have following simulated data of 2500 persons regarding the incidence of a rare disease over 20 years ...
2
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1answer
28 views

How to detect variable seasonality pattern

We have predicted and actual (daily) data for past 3 years. We use 90 days of data for prediction. Generally our predictions are very accurate, but we receive unusual traffic for few days/weeks ( like ...
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0answers
14 views

Comparing two data sets for a trend in the data

I have two data sets ( have only access to the statistics of data sets like mean, percentile, count etc but not the data it self). I am interested if I could have a metric which can answer below ...
4
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2answers
53 views

Analyze trend given a set of points

Suppose I have a set of N values representing EUR/USD rate... [ 1.10 , 1.20 , 1.25, 1.20, 1.19 ] Which is the simplest way for analyzing if values tend to raise or tend to fall? I'm looking for a ...
1
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0answers
13 views

Making a Time-series Stationary: Order of Operations

Following various sources including this post, which is the correct approach to making a time-series stationary? Remove trend Remove seasonality or Remove seasonality with estimated trend ...
1
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1answer
35 views

How can a 95% confidence interval not overlap with my trendline forecast?

I used holt winters in excel to forecast 12 moths ahead based on 40 months of historic data. Then I ran a monte carlo simulation to create 1000 scenarios and computed upper and lower bounds to create ...
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0answers
24 views

Trend modelling interpretation

I have estimated the following two models: $$ Δy_t=0.015-0.410Δy_{t-1}-0.220Δy_{t-2} $$ and $$ Δy_t=0.400+0.00145t-0.150y_{t-1}-0.325Δy_{t-1}-0.220Δy_{t-2} $$ (Note that $y_t$ is the log of monthly ...
0
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1answer
88 views

How to determine “trendiness” of a time series

I'd like to be able to compare two timeseries as to their level of "trendiness" to determine which trends better. For example, assume two stocks, Google and IBM. Would like to understand approaches to ...
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3answers
62 views

Interpreting moving average chart

Using 26 years monthly price of coconuts I plotted the 2 period, 3 period and 4 period moving average charts. Every line seems to lie overlapped. What can I infer about the trend from this chart?
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0answers
10 views

How to data mine google for most popular things out of a set?

Let's say I want to get the list of the top 5000 most searched biomolecules on google - how would I approach such a problem? One possible solution is to fetch the whole pubchem/pdb database and run ...
0
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1answer
99 views

How to detect peaks and trends within time series data?

I've been trying to detect defrost cycles using refrigeration data. I have a sensor within the fridge which simulates a product and measures the temperature every 15 minutes. Usually, based on the ...
0
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0answers
31 views

Identifying deterministic trend vs stochastic trend

In EViews for Augmented Dickey Fuller Test I get a p value of 0.4326 .I have few questions regarding this? 1.Does this mean I have a stochastic trend or a ...
0
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1answer
50 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, ...
2
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0answers
24 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 ...
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0answers
15 views

Temporal Data set

I have a fishery data set of fourteen years in a tropical region. This kind of information is quite rare in ecological studies.The data were monthly collected and the set has 2 annual gaps and a gap ...
3
votes
1answer
75 views

Most accepted theory to analyse trend in data series

I have pollutant concentration for long period I want to determine trend. I have read some of the question answers in this blog regarding same . I have few queries. What is most accepted theory to ...
2
votes
1answer
50 views

Interpreting the result of decomposing time series

I don't have a lot of experience working with time series data. Now I have a 3 year, monthly data for several entities (you can think about them as different stores), that I would like to do some ...
2
votes
1answer
18 views

How to display potential outage when usage fluctuates greatly among customers?

I work for a Health Information Exchange. We have numerous "participants". Some send hundreds of messages a day, some might go a day or two without sending any messages. I'm creating a daily report ...
3
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0answers
85 views

chi square for trend - SPSS

I have followed fourth-year university students for ten years, recording their attitudes to a particular lecture. The outcome is binary (good-bad). I have 10 rows and 2 columns, meaning year and ...
2
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1answer
50 views

Common trends with Difference in differences

For OLS to have good properties, we should assume that $E(u|X)=0$. When using DiD, is it then this assumption which requires the so-called common trend assumption (need for the DiD to have good ...
0
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1answer
27 views

Change detection in trending degradation data

I'm working with degradation data and are trying do use change detection methods to detect repairs. Since I'm looking for repairs I'm only interested in positive changes. Between the repairs the data ...
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0answers
53 views

Should outliers in a time series be removed before or after detrending?

I am doing a classical time series analysis. When do I remove outliers in the data? After detrend or before detrend?
4
votes
1answer
34 views

Trend Visualization of N time series

I have about 500 time series with different trends, and each time series represents a given nb of transactions. (Volumes follow a long tail distribution). I would like to plot a summary graph on ...
0
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0answers
42 views

Dealing with seasonality in time series with no trend

I'm working with quarterly time series data. The series does not have a trend but fluctuates around more or less a constant mean. I observe weak seasonality such that the values are somewhat lower on ...
0
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0answers
37 views

Does downsampling affect trend

I have a large set of time series data for which I want to identify the trend. For trend identification I am using a Simple Moving Average (SMA) function over my raw data in order to smooth them ...
2
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1answer
23 views

Approach for estimating expected time required (Regression analysis)

I am analyzing data from a factorial experiment with between subject factor Purifier (two types A and ...
0
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0answers
47 views

How to determine significant difference between two sets of time series data?

I have 2 sets of time series data. The data were collected from individuals who were matched (via propensity score matching) prior to collection. The only difference is that one set of matched ...
0
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0answers
45 views

How to find if there is a trend in a time series and stationarity

I would like to conclude on a given time series that if it has Trend or not. I have carried out a cox-stuart test in R and have decomposed to inspect the series visually but still a bit confused on if ...
0
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0answers
15 views

How can I identify if there is a trend?

We need an indicator/model that identify properly the market momentum of a certain array. Ideally we would like to have an indicator that swings from two given value and identify if an array is in ...
0
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0answers
7 views

What measures can be applied to the arrival of unique website visitors to asses whether there is an increasing or decreasing trend?

I am looking at the logs of arrivals of unique visitors to a website. I can plot the data as a histogram, and look at the plot to get an idea of whether there is an increasing or decreasing trend in ...
0
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1answer
74 views

How to translate percentage decline into a regression slope?

I want to model a negative relationship of count/binary data over 10 years with a known value for the decline rate (in percentage). However, I have problems in calculating the correct slope value for ...
0
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0answers
22 views

I am interested in conducting a trend analysis with random subject/item intercepts/slopes, in R

I have a dichotomous outcome variable and am using an IV with three levels. Is it possible to run a trend analysis in which the DV is the likelihood of success, while also including random subject ...
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1answer
55 views

Is there a rising trend in Number Series

I am trying to build a stock screening utility. What I am trying is to find if there is a rising trend in a time series of profit margins of a company. I know there can be dips in some years but I ...
2
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1answer
69 views

Statistically testing for a significant difference between two slope values [closed]

I have five trend lines plotted in excel of number of prescriptions of a 5 different drugs over time (MM/YYYY) and I want to test the statistical significance of the difference between the slopes, to ...
0
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0answers
48 views

Detrending or Differencing in order to make a series stationary?

I got several time series for which I want to find out if they are stationary or not. So I computed for each series the kpss.test(). But before making further ...
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1answer
58 views

The constant term after 1st differencing

My instructor stated that when the dependent variable is 1st differenced, the constant term represents the deterministic change or trend in the dependent variable. When I search for information ...
0
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0answers
101 views

determinstic trend in VAR-models

I'm asking myself the following question. I want to build a VAR-Model with 6 time series A, B, C, D, E and F. I analysed every series univariate and I found out that A, D, E and F are stationary and B ...
0
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0answers
15 views

How to adjust rank for ad for its recent trend in click-through-rate?

I am building an optimization service for an Adtech company. For ranking ads in terms of performance, I am using formula: Log(impressions)*eCPM. Impressions means the number of times ad was ...
3
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0answers
67 views

Seasonal Kendall test and the Mann-Kendall test

I am trying to detect trends using non-parametric methods but I'm a little confused as to when you should apply the Seasonal Kendall test. Don't get me wrong I know you apply it when you have ...
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0answers
19 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 ...
0
votes
1answer
39 views

Deterministic trend and noise

I have a chicken-egg problem in time series: How do we remove the deterministic trend in time series when you have a guess that the noise is non-normal? How do we check if the noise is non-normal ...
2
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1answer
113 views

markov chain with probability trends

I have clients with debts that can pass from states own 1 bill, own 2 bills, own 3 bills, leave the service, new debtors and owe nothing. So I could calculate the probabilities of being in state ...
0
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2answers
165 views

fitting a cubic polynomial to a trend component of time series

I have 295 observations of two variables, of which here are a few: ...
4
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2answers
189 views

Do you see trends in my residual plots?

Do you see trends in my residual plots? These residuals plot show the standardized residuals against fitted values, origin period, calendar period, and development period. The patterns in any ...
0
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1answer
21 views

How do I know if this jump is going against the downwards trend?

I'm looking at some accident statistics and have a question about how it's reasonable to interpret the data. The numbers are fatalities in traffic accidents, and I want to discuss a newspaper article ...
4
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0answers
80 views

Test for trend (ordinal predictor, continuous outcome)?

I have measured a continuous outcome variable in three groups of patients, where the groups are related to the severity of disease (control, mild disease, severe disease). I would like to test for a ...
3
votes
0answers
42 views

What is the ‘Pile-up Problem’?

In methods of trend-cycle decomposition, what is meant by the 'pile up problem'? How can the pile up problem be detected? Can it be detected by the method of visual inspection? If so, what are the ...
3
votes
1answer
62 views

Time Series Stationarity

I am confused of why my Dickey-Fuller test is significant (which implies stationarity), while the time series clearly exhibits a deterministic trend?
1
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0answers
34 views

Is smooth.spline appropriate for presenting the trend of chemical concentration in a catchment [closed]

In my case,the Electrical Conductivity (EC) values are measured daily in some pints of catchment from 2007 to 2014, and around 20% data are missed, due to without probe or flux. To presenting the ...
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1answer
37 views

I am wondering what model to use [closed]

I am trying to do an analysis of popularity growth, in particular of the rate of growth in play count for artists on an online music streaming service. I want to create a postgresql db filled with ...