Suppose I want to compare algorithm runtime performance (measured in seconds) of different algorithms for the same problem type. There are several problem instances for this problem type on which the algorithms are tested and performance is measured.

As far as I know, the following is true (please correct me if not!):

- We want to compare 2 algorithms on 30 independent test instances: In this case, one could use a unpaired Student's...

Test wanted for comparing algorithms]]>

The problem can be outlined as below where a sample can be split into a number of categories (A,B,C,D) :

Proportions from Sample 1 Proportions from Sample 2

A..............................X...................................................................X

B [COLOR=rgb(239, 239...

[URL='http://www.talkstats.com/threads/advice-please-statistical-testing-a-number-of-proportions-from-two-samples.71327/']Advice please: statistical testing a number of proportions from two samples[/URL]]]>

categorical control variables in SEM using AMOS]]>

- The paper is essentially all 1) math, 2) my logic otherwise and 3) a couple of claims about scientific opinion (that, from my searches, no scientist has written directly about).

- Consequently, I'd like someone who knows what they're doing, re Bayesian statistics, to tell me if, and where, I've gone...

Immortality & Bayesian Statistics]]>

Essentially it’s a clinical trial where we gave patients a dye and checked for it’s presence in the abdomen using a fluorescence camera (intervention) and a plain white light camera (control). We have a binary outcome (present or not) as well as signal intensity (continuous variable) for the intervention data.

I want to see whether the fluorescent dye was superior to the control and what the probability is

Over time that the dye is better than the...

Which test to use]]>

But do I need to be careful with ratio data because this essentially treats two related variables (golgi size and cell size) as a single variable. Are there more...

Ratio of sizes data]]>

I am trying to determine what statistical measure of association I can use to determine whether there is a relationship between these two variables.

I assumed the best way to do this is to convert the two variables to percentages so that my hypothesis would be: there is a positive correlation between the percentage of...

Can you use correlation for percentages?]]>

First of all, thank you for taking the time to read this and hopefully provide me with an answer. Context: I'm an MD, currently in my third year of my PhD in adult oncology.

I'm doing a study regarding treatment-related mortality. In this study, we have roughly 2000 patients included (5-year cohort) , all adults with cancer. In this population we want to look at factors that increase the chance of treatment-related mortality. I've done previous studies looking at overall...

Which competing risks survival analysis to choose]]>

I write to ask an advice about which type of analysis I should perform in the following situation.

I have 2 groups:

- treatment group
- placebo group

- session 1 (pre-treatment)
- session 2 (post-treatment)

- dependent variable
- mediator1
- mediator2
- mediator3

mediation in a mixed repeated-measures design]]>

We are conducting a finance event study on abnormal returns and unexpected trading volume.

Our data consists of abnormal returns/volume (not normally distributed, leptokurtic, log transformation not enough) for an industry index security for 250 consecutive trading days for estimation period, and the following 250 consecutive trading days out-of-sample, in which we have three sets of 5 days of event periods.

We would like to test each of these days in each event period...

Finance event study on abnormal returns for one security - non parametric test needed]]>

I am wirting my thesis and I would like to test the effects of an mindfulness Intervention (independent variable) on reducing depressive, anxiety and stress symptoms (3 dependent variables). I have a pre and post-test for this and I would also like to include a control group.

Which test do I have to use for this and how can I calculate my power to knwo how much particpants I have to include for this study?

Thank you in advance

Kind regards,

Naomi]]>

Examining the moderating effects of negative affect on Perfectionist Self Presentation and social media addiction

I’m thinking I got my moderator wrong. It should actually be Perfectionist Self Presentation that would moderate the relationship between negative affect and social...

Does this make sense]]>

(1,0,0) for 3 rows

(1,1,0) for 3 rows

(1,0,1) for 3 rows

I guess you could say I need help learning rep( ) in the matrix function. Thanks for your help.]]>

Thanks in advance ]]>

I have searched a few and saw different types of table preparation for multilevel logistic regression analysis.

As a new thesis student, I am getting confused. Now, How can I create a table with multilevel logistic regression model with these 3 level variables?

Level 1: Participant level : child_age, breastfeeding, vita_a, vaccination, nutritious_food,

mom_age, education, workstatus, hus_edu

Level 2: Household level : wealthindex...

Interpreting a 3 level multilevel logistic regression model]]>

I am currently using BDHS 2014 dataset.

I want to execute a 3 level multilevel logistic regression model by using 'gllamm' command.

Here is the leveling:

Level 1: Participant level : child_age, breastfeeding, vita_a, vaccination, nutritious_food,

mom_age, education, workstatus, age_frst_brth,

Level 2: Household level : wealthindex, med_exposure, toilet_fac, fam_membrs, dec_childcare, dec_momcare

Level 3: Community level : residence...

gllamm command for 3 level multilevel logistic regression model]]>

I am very new with statistics and I am looking for some advice and ideas.

I found a lot of information in Google, but some times too technical or some times not sure if useful in my case, so I was hoping someone can give me some light.

I have conducted a survey to understand the quality of the documentation that I create for my clients. I have sent to my full list of clients (170) and I only got 13 responses, all of them completed 100 de survey.

In the survey there are three...

Survey results analysis]]>

I'm currently conducting a study looking at the relationship between sleep, stress and fatigue in a student population. I'm unable to conduct correlation type analysis with this study. I know that some form of regression analysis would be best to investigate these relationships, however, am finding it difficult to single out which type as each factor affects the other. Would running multiple linear regression analysis be appropriate in this case?

Any help would be hugely...

which type of regression analysis to use]]>

I'm trying to come up w/ a way to predict coupon mix. I know 100% of my customers will take a coupon, but I want to predict the mix of types of coupons customers will take. I can't use regression analysis... does anyone have any suggestions?

Thank you!]]>

The big issue is that as per my theory tested I am not interested at all in the main effects of demographics but only in the interactions with the condition variable. Moreover, there are extreme collinearity forces among the demographics e.g. income and education etc.

Hence, I...

Logistic Regression Models Without Main Effects?]]>

I think that for the above, isn't the AIC, BIC the most arguable? I would look at autocorrelation plots, but I am trying to see what is missing in this and how to handle on the multiple models. Please elaborate with details, and thanks]]>

solve some challenges I have came accross in my job.]]>

Just a thought, but could...

Limitation of Insurance Liability]]>

If you're interested in a Quant Psych PhD, but you're not particular about what area you study within it, what specific Quant Psych areas would make you most employable

So for example, is there a certain kind of analysis (e.g., multilevel modeling) that is currently in very high demand in industry/government?

Or is there a certain area of application (eg, genomics) that is currently in very high demand in industry/government?

As examples here are some...

What area of Quant Psych most lucrative / best prospects for PhDs?]]>

I’m running a surveylogistic procedure with complex sampling variables (stratification, cluster, and weight) to account for sample size in my estimates. Everything is suspiciously significant. Suspicious because when I run the model on a single year some...

Sample Size Affecting my Estimates]]>

I conducted a survey where respondents need to evaluate different combinations of firms and need to decide how attractive they are to them. My survey includes different factors with different levels. I already generated the orthogonal design and got 18 cases. However, I did not tick the option of holdout cases because I would have too many combinations for my participants. Does my survey lose credibility because of that?

Each of the 18 Company combinations is ranked INDIVIDUALLY...

Need help with SPSS CONJOINT ANAYLSIS]]>

I am a Master student and just finished collecting data for a survey, a vignette study. I have a total of 12 vignettes, followed by 4 question (the same questions after each vignette), which measure Preference on a 5-point Likert scale. Each participant was randomly shown 3 vignettes. The vignettes are composed out of two variables: Type of Task (4 different task types) and Urgency (perception of low, high, or no urgency). Hence, 4 x 3 = 12 vignettes.

Unfortunatly, I have no...

How to analyze a Vignette study in SPSS]]>

Hi,

I am a PHD student and just finished data collection for my third study, which was a vignette study. I designed an online questionnaire with 30 different scenario's, or vignettes, followed by a block of 7 questions (the same questions after each vignette). Each participant was randomly exposed to 5 vignettes, out of the total of 30. The vignettes are composed of two variables: a topic (ranging from low to high in intimacy, 5 topics) and social tie...

How to organize vignette data in SPSS]]>

I thought I might start a thread which showcases the graphics abilities of R. I'll start it off with one I just made.

This thread was also inspired by bg and trinker claiming that this could never be done in R.

Of course it can you just won't be able 1) to showcase it in R but it works nice with any non IE browser or...

[R Graphics] Beautiful graphics thread]]>

I've been unable to run an independent t stats on the following data and I couldn't fix the problem.

Both variables are set to Numeric and the First(Section) is Nominal while QuizGrade is Scale

Section QuizGrade

1.00 100.00

1.00 33.00

1.00 92.00

1.00 33.00

1.00 98.00

1.00 55.00

1.00 100.00

1.00 99.00

1.00 57.00

1.00 72.00

1.00 50.00

1.00 100.00

1.00 100.00

1.00 92.00

1.00 85.00

1.00 76.00

1.00 52.00

1.00 52.00

1.00 89.00...

a. t cannot be computed because at least one of the groups is empty. SPSS]]>

I am pretty new to the times series analysis and I am having a hard time analyzing on EVIEWS one where there is a strong seasonality component,.

1. Since the variance wasn't stationary I applied a log transformation to the series.

Initial statistics:

After the Log transformations:

Then I check if the series was stationary, and after checking the correlograms (below) I decided to run the X11 to deseasonalize the series...

Issues with seasonality and ARIMA terms.]]>

At work I'm trying to explain how a group (X2) can capture a higher % of both categories (A & B) than Group X1, but still have a lower overall % than X1.

I've run into this type of thing before where an average falls outside the range of group averages, but for the life of me I cannot explain what is going on to a layman.]]>

I don't know what's wrong but I've been trying to compare the means of two independent groups using the independent t test in SPSS but I fail each time I try.

This is the message I get:

Warnings

The Independent Samples table is not produced.

a. t cannot be computed because at least one of the groups is empty.

Anyone help me solve this problem?]]>

What tests to use?]]>

I am trying to use this in my interpretation of the results of an interaction variable and need to calculate the OR and 95% CI for the difference in difference if this makes sense.]]>

I have a data set with 80 patients. At baseline we measured all with a symptom severity measure (t1) and three other variables of interest (v1, v2 and v3). I have followed upp all patients one time at 12-18 month after baseline assessment. In the follow-up we repeated the symptom severity measure (t2) employed at baseline. I want to explore if v1, v2 and v3 effect symptom change.

If I run a linear regression with t2 as the dependent variable and t1, v1, vt2 and v3 as independent...

Regression or Mixed Model?]]>

So I have a question that asks to find the margin of error from a confidence interval for a population mean, the confidence interval has a length of 162.6.

The only way I can find to obtain the margin of error is with zalpha/2 x standard deviation/ square root of n and I don't have any of that information. Can someone explain to me how to figure out this problem? I feel like it's really simple but I can't for the life of me figure this out! My textbook and professors notes aren't...

Margin of Error of a Confidence Interval]]>

Friends, I would like to know your opinion, why most medical research is perfected by analysing the confidence interval. Draw conclusions only from a comparison of the mean values and the value of P.

If the CI strives for 1, or the value of p is too small (for example, p = 0.008), then clinically such a difference is either not significant, due to the rarity of the event or its insignificance, or based on a CI close to 1, such a difference or such RR is...

Problems of statistical analysis in clinical practice]]>

Any idea?]]>

I’m currently working on a thesis and I’m unsure about what statistical tests to run.

My present study examines the potential relationship between attachment styles and the presentation of codependent traits. The goal of the study is to determine the attachment styles of college students and determine if any attachment style is significantly related to the development of codependency. Also, this study hopes to identify gender differences among the presentation of codependent...

What statistical tests apply to my study]]>

1. Last year, a manufacturer produced 300,000 DVD players. Of these, approximately 1% were defective. Assume that a simple random sample of n = 150 players is drawn. Use the Poisson approximation to the binomial distribution to compute the standard...

Need help with two problems involving Poisson Distribution]]>

I did a dependent t-test for a medical research, it was comparing before and after measurements.

So the dependent t-test should be the right test to use.

The after measurements have a wide range.

And then the client provided me with another piece of information: "it is very normal for the after

measurements to go up to 20. <20 is considered normal, 20-30 prolonged and >30 abnormal".

I am wondering whether this impacts how I should run the paired t-test? Do I need to do some...

Dependent t-test with extra information provided]]>

Does anyone have suggestions for adjusting scores from a psychometric assessment that appear to suffer from ERS? I'm looking for an applied approach, perhaps a formula that I can use in Excel to adjust the data.

Thanks!]]>

I have 10 questions and 2 sources for answers. Each answer has it's own confidence score. Answers from source 2 has overall better result but in two questions the answers had 0 confidence score. How can I evaluate which of these two sources is better? Thanks

]]>