I want to perform trend analysis to know whether the overall prevalence is increasing or decreasing over the 9 years.]]>

Minitab 17 Discrete X Discrete Y Question]]>

I was about to run a single-species single-season occupancy model on habitat variables for my tropical mammal data in R. One of my statistic mentors told me I might need to convert my data on distance to road and distance to rivers by using LN or Log10. It seems that he also was not too sure, as he mentioned that the need to convert data depends on my research question and stayed rather vague on his opinion about my data set. I do not really understand...

Convert data by LN or not?]]>

How to calculate the mean and standard deviation of parameters of a function that exists in both discrete and continuous version]]>

Can someone help me add 95% confidence intervals to the Predicted Y below. I understand calculation of Predicted Y but I'm not sure how to calculate the confidence bands around each value of Predicted Y.

Any help would be greatly appreciated.

Thanks,

Tim]]>

I need to produce a probability for a vehicle and a pedestrian meeting along a 1km road.

Here is what I know:

•1km road

•cars take 3 minutes to travel

•pedestrians take 12 minutes to travel

•30 cars an hour

•20 pedestrians an hour

The cars and pedestrians may also be grouped or evening distributed on the road as well.

This is a simplified version of what I’m trying to achieve, but i need it simple so I can explain this to my non-mathematical boss. It’s so we can make an argument that...

Probability of Vehicles and Pedestrians meeting]]>

Goodman and Kruskal's gamma statistic for likert scale data]]>

I am trying to compare variables mean and std deviation across three samples. Is oneway bonferroni test is the best way to do it? If yes, when reporting P value in descriptive statistics table, which p value should be included? ( there are p values for each row column mean comparison and another one for F test) Thanks]]>

I am writing my thesis for medicine about postoperative complications of a disease (IBD). The dependent variable in this case is whether the patients had a post-operative complication or not (binary) within 30 days of their operation. The sample size for my study is n = 62.

I have collected numerous (32) independent variables (age, sex, different lab values, time of operation, etc), some are continuous and others are categorical variables.

I have so far done an univariate analysis...

Multivariate analysis for Medicine Thesis]]>

I hope I have posted in the right section.

I am a master's student currently working on a zoo project with monkeys. I have some questions regarding which tests are appropriate. I would like to compare the overall activity budgets of each individual in each condition, rather than do a group comparison.

The study is on 9 monkeys. I collected 5 months of data and have two conditions, before enclosure was changed and after. For each condition, I have 12 hours of data for each...

Which tests for activity budget comparison]]>

I am trying to assess change in an independent variable based on a regression model. Basically I am trying to predict sales from the percentage of calls; at Baseline I predicted sales from percentage of calls and obtained a model. My next goal is to create a trend analysis of what the hypothetical sales would be if the percentage of calls was increased to a given value. Here is where it gets difficult.

If percentage of calls range from 0 - 100%, and I want to know what the...

Hypothetical Change in Independent Variable]]>

My question is...

How many shots at a target are required to determine the accuracy?

What attributes, factors or terms should we be talking about when comparing one competitor’s results (precision) to another?

Some times competitors take 3 shots and brag about how...

Target Accuracy and Precision]]>

Because there are only two out of five events happening, why are SAS and R still able to give the median survival time, which is 5.9539 (in moths)?

Here are my codes in R:

pfs_fit <- survfit(Surv(pfs_m, pfs_stat) ~ 1, data = data)

os_fit <- survfit(Surv(os_m, os_stat) ~ 1, data = data)]]>

Baseline measure (from a leg at random)

PHASE 1: Leg 1 - exercises, Leg 2 does nothing

- Measurement again of BOTH legs at 6wk

PHASE 2: Legs 1 AND 2 BOTH do a different...

Is this a 2-way or a 1-way ANOVA?]]>

Is there a way around it?

Or is it fine to use?]]>

I'm coding a program that identifies appearances of a lowercase "x" in a base64 encoded string. Like the following:

DWADCrxV+PhR4zxkQrIMUtarkN11aitHI8DEnzyG19CD...

I know the probability of finding at least one "x" in a sequence of 10 chars.

My doubt is about dealing with multiple sequences of 10 chars. I mean, as I see, they can be overlapping or non-overlapping:

DWADCrxV+P hR4zxkQrIM ...

DWADCrxV+P WADCrxV+Ph ...

To...

Probability Over 2 Sequences Of Trials]]>

I am getting lost in the definitions of univariate, bivariate and multivariate tests.

I have gone through the process of completing several statistical analyses. The independent variable, treatment modality, is categorical with three distinct/unique groups.

I have tested group differences on assessments and clinical measures using: One way ANOVAs, Chi-Square Test for Independence and Kruskall-Wallis H test.

I'm getting very confused... are these all multivariate tests because the...

Was this univariate, bivariate or a multivariate test?!]]>

I have been developing tutorial for this course and need critical reviews from similar faculty.

Can you help?

Moderator: I am not selling. I just need to know if I am on the right track.

If this post is not acceptable, just delete it. Thanks.]]>

Following my viva, I have been asked to do an internal validity analysis using Cronbach's alpha.

Qu1. Can anyone advise should this be done on the whole sample n=30 (mixing controls and...

Cronbach's Alpha for a new test. tested w control (n=15) and clinical group (n=15), should I run it on whole sample (n=30)or separately on each group?]]>

Doing 100 rolls I should expect to see around 17 doubles.

I then added up the values for the critical value and put them in a calculator and got

Does this mean that it's unlikely to get better results than the ones I achieved? or did my test fail and was weighed heavily not by random occurrence?

I'm wondering if I made the...

Need some help on my calculation]]>

Does this mean I have also performed mediation or do I need to that separately?

I am very new to logistic regression ... and within a learning process.]]>

Sorry, I am new to stats.]]>

This might sound like a ridiculous question but I'm looking at relationships that have not been investigated before.

The experiment is a repeated measures design and looking to recruit participants between 16-25.

I am not sure how many participants in going to need. Can anyone help?]]>

I am about to restart my education at University but I have forgotten most of what I have learned. Here to refresh my knowledge and expand it.]]>

Data for x

Year Response Q1 Q2 Q3 Q4 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13

2017 1 9 9 22 3 4 11 7 16 12 23 6 9

2017 2 63 30 91 15 33 51 43...

Forecasting or Prediction for Categorical Data]]>

Any thoughts....?

I have longitudinal biomarker data that is routinely gathered, so will not be at specific time points. I want to identify trajectories of biomarkers in a disease to identify subpopulations that might have increased risk of adverse outcomes compared to other trajectory groups. My concern is that this model requires specific time points of biomarker observations for all subjects in order to work?

Any thoughts or suggestions would be appreciated]]>

I have a machine learning algorithm that is supposed to help users get a particular number closer to their goal. My issue is that I need to determine an efficiency metric for the current iteration of the algorithm but have been having a rough time so far. I suspect at this point im grossly overthinking things or just on the wrong path altogether.

Please help: Finding Efficiency of Algorithm on System]]>

Relative Difference in the Mean with a confidence interval]]>

Need to mark numbers violated ±20% from nominal value.

Should I use std dev, mediance, variance?]]>

I have three sets of data about a particular cell line under different three different feeding strategies.

Each set is divided into three subsets for cell operation period.

E.g.

Feeding X - Feeding Y - Feeding Z

Feeding X:

Behaviour in time period 1, 2,3

Feeding Y:

Behaviour in time period 1, 2,3

Feeding Z:

Behaviour in time period 1, 2,3

I want to analyse how the cell perform under the three feedings X Y Z.

Any thoughts?

Thanks!]]>

Residual Plot Interpretation]]>

I have measured the flow (continuous variable) over a minute of a certain device A using two different testing machines B and C for a verification procedure. Each machine B and C has an error consideration of +- 0.05. The flow wave is characterised by a repeated morphology that repeats according to a frequency f. So essentially, I have two continuous signals in the time domain that should be the same but due to error are not...

What statistics test to use for signal analysis]]>

Any references also welcome. Thanks.

Jameswei]]>

I'm using the tolerance interval function in minitab, my sample size is limited to 7 (the parts are expensive blah blah)

I've heard to be statistically significant a sample size of 30 is recommended but in practice how low can I go for sample size when using a confidence / tolerance interval? Is there a generally accepted minimum number of specimens??

Thanks]]>

I am a research student working in the dairy field and I am quite confused with the experiment I did recently.

I have three kinds of milk(1, 2, and 3 with different protein and fat content) and I tested three inoculation concentrations(treatment) for each of them, and there are three replicates. I think for milk 1 (see below) it is a 3 × 3 completely randomized block design, which incorporated 3 treatments and 3 blocks (replicate trials).

And for...

Confusion about randomized completely block design]]>

I have a series of 163 serial numbers that fall between 77.681.001 to 78.786.366.

The item that these numbers have been assigned to have all now been produced and sold, but the total amount in circulation is not known. it is estimated the number could be 1,000 to 5,000 based on past and similar production runs.

My question is, can a statistical process be applied to find an estimate of how many items were...

How to estimate numbers of a production run]]>

I'm from a 3rd world country and am interested in using statistics for research purposes, and these statistics would cover a broad variety of topics but mostly focused on political and economic issues. Although there is a governmental body that specializes in statistical data and analysis, I figure I'd ask a forum dedicated to statistics on the best source for cutting age statistical information. If this isn't the right place to ask this question, I ask for correction on...

Hello]]>

So I thought that a less than p value is equal to 1-[two-tailed-p-value] but on a TI83, I see that this is not the case. The reason I need to know is I am trying to make my own calculator using Apache commons math3 library, their function for a t test gives me a two tailed answer and I also need left and right tailed given that answer.

Below shows what I typed into the calculator and what...

P-Values for less than t test two sample differ by .002 when applying 1-[two-tailed-p-value] on a ti-83]]>

Do i have to use the formula 1)y=b+b1x1+b2x2+b3x3

=81+0.48*50+0.46*30+0.06*100

=124.8

b1= age b2=BMI b3=blood glucose b=constant

2)

Difference =b1*(difference in x1)

=0.48*20

=9.6

Is this correct or am i doing something wrong?

Thanks.]]>

I have had members of staff from two different departments complete surveys on their opinions of waiting times:

Example question:

Do you think waiting times have: increased, decreased, stayed the same.

Results:

Department A: 30% staff felt waiting times had decreased.

Department B: 50% staff felt waiting times had decreased.

I want to compare the opinions of department A to department B. My confidence intervals overlap so I thought I could do a t-test to prove that there is a...

Which comparative stats test to use?]]>

suppose you have several (~3-4) measures of an economic variable. These measures all come with some degree of measurement error (noise) and it is a-priori unclear which one best represents the underlying phenomen (which one intents to capture). To complicate things, the samples of the measures only partially overlap.

Is there a method to combine the measures to arrive at "a best measure" (i.e. less noisy)? Ideally, the method would result in a point estimate and a confidence...

Combining proxy variables to estimate true underlying variable]]>

1. The first component of my study is relatively simple: I am using ecological momentary assessment (EMA) to assess whether, on an intra-individual (within-subjects) level, alcohol consumption moderates the relation...

Help with a model: can the strength of moderation be used as a variable?]]>

Business partner is over a QA function for completed contracts. His team checks for generally 18 specific items, all are go/no...

Sampling Plan Help]]>

For example, I am currently doing a sensitivity analysis in checking how the volume of a spherical region-of-interest (ROI) influences comparisons of brain activity when comparing participants before and after a training intervention. There are 4 ROIs, and each have 3 different sizes. This is the table of p-values:

4mm 6mm 8mm

ROI1 0.020 0.059...

Multiple comparisons of dependent (and independent) tests]]>

I have following problem: I do measurements of the formation of a product at two time points (t=0 and t=15), each in triplicates. Afterwards I calculate the mean value + the standart deviation of each time points. Now I do a linear regression (time on x axis) to obtain the slope, which is the output I want to know. So far so good, but since I have standart deviations at both y-values, I also need a standard deviation of the slope and here I am a little confused...

Error weight in 2 point linear regression]]>

"AIC is used to evaluate ARIMA commonly. AIC criteria are only used to compare nested models. This means that the smaller model (e.g., 0, 1, 0)must be a subset of the larger model (1, 1, 0). The tests are not legitimately used to compare, for example, (1, 0, 1) and (0, 1, 0). And they could not be used to compare models in which a different value of...

AIC in ARIMA]]>

identify var=spend scan esacf minic;

ESTIMATE p=(

ods graphics off;

when I ran this I got the following warning which I have never encountered in ARIMA.

Warning: The model defined by the new estimates is unstable. The iteration process has been terminated.

Warning: Estimates may not have converged.

Any...

ARIMA issue]]>