This is my first thread on this forum so please bare with me as I try to be as concise as possible, I'll then write down my questions at the end of the thread.

I'm working on some class notes, and stumbled upon this problem that confuses me on some point:

"The drying time of a certain type of paint, under fixed environmental conditions, is known to be normally distributed with mean 75 min. and standard deviation 9 min, i.e. N(75,9). Chemists have added a new additive that is...

Hypothesis testing]]>

I am performing a meta-analysis in R using the meta package. For binary variables, everything works perfect. However, for continous data (using standardized mean difference as effect measure), I have one problem.

I am performing subgroup analysis bases on study design (RCT, prospective etc.). However, the forest function does not give subtotal N but it give a 'dot' (= ., see example below) instead. If I pool all subgroups to an overall effect, it will give a total N, but it still does...

[meta] Forest plot does not give subgroup total N]]>

I am reading an article at which authors used an effect size that it's totally new to me and I do not know how to interpret it. I would appreciate if anyone could explain its meaning or provide any reference about its interpretation. Below, I paste some sentences from the original article at which the authors' explain how data were analyzed, highlighting in bold the effect size description.

We used linear regression model (...) Analytically, we regressed one of the outcomes...

Effect size in regression]]>

I'm doing research about relationship between energy consumption and GDP growth of European countries in timespan of 20years.

I would like to test a hypothesis : energy consumption does affects GDP growth. (if does, how? Unidriectional, bidirectional)

As I searched through articles on this topic, most of them were using method of Granger casulity, so I decided to take this method, too.

Firstly I should make some test for unit root (to check if my variables are stationary or not)...

Panel data analysis - Granger casuality]]>

The effect of 1 continuous variable ("fixed factor"?) on a categorical DV controlling for 1 categorical variable (covariate) and 4 continuous variables (covariate).

I can also work with the continuous variables transformed into categorical variables.

Isn't this Binary Logistic Regression? How do I go about "controlling" in SPSS? As in, for the BLR test, there's no way to tell SPSS that some variables are covariates.. I guess SPSS does what I want to do it...

Which test to use?]]>

Also, there is no multicollinearity and have controlled for hetero, auto and cross sectional dependence through Driscoll and Kraay SEs. Due to endogenous focal variable, 2sls is used.

Group low on index has few variables including the focal one, significant. However, group with high...

Predictors insignificant & F-stat is highly significant!!]]>

I know that type 2 is failing to reject the null when its false but im not sure how increasing sample size reduces type 2 error]]>

I have one outcome variable (A), many predictor variables (X,Y,Z,..) and three groups (clinical groups I, clinical group II, and one control group). I would like to see if there are differences in predictors of A between groups (at least between the two clinical groups).

I was thinking fist to do a standard regression separately for each group (if I have big enough sample for each group), then probably to use the predictors that are in common and run another regression...

How to compare differences between groups in predictors of an outcome variable?]]>

Sex is the only categorical covariate and it takes on the value

Sex = 0, for female

Sex = 1, for male

I want to interpret the intercept of this model, that is the estimated mean value of Y when all the covariate coefficients are zero.

But I don’t understand how to view a zero coefficient in front of a categorical variable such as sex. If all coefficients are zero, am I looking at 0 height, 0 weight, 0...

How to interpret the intercept in a regression model which has a categorical covariate?]]>

Can someone please help me understand why the standard score is a linear transformation since both mean and standard deviation depend on X?

thanks]]>

I opted for statistical significance among p1, p2, p3 at (w1 and w2 and w3) and at (s1 and s2 and s3). then i opted statistical significance among...

alternative/opposite to piecemeal statistical approach?]]>

I'm categorizing by time, so eg.

3-6am : 5 prey, 2 predator

6-9am: 10 prey, 1 predator ect.

I've tried doing a 2 way anova, and chi squared test but I dont think theyre right because I'm not getting values?]]>

I basically want to compare two retail centres (UK) and the customers perception of the atmospheres of them. In another survey judging the retail centres overall one was ranked very highly and the other very poorly, so I expect my data to reflect this.

So firstly i have some demographic questions which i plan to just...

Desperate need of help for my undergraduate dissertation]]>

After performing a subset selection, the remaining two choices are

Model 1, which has 7 covariates and a lower BIC.

Model 2, which has 11 covariates and a higher adjusted R^2.

Using the BIC criteria, you select the model with the lowest value.

Using the adjusted R^2, you select the model with the highest value.

So in this case, which model selection criteria would take precedence?]]>

If it can't be used for that, would anyone know of a reasonable method to compare the R-squared of the two regression outputs for different time periods. Basically I am working on a pre and post study and want to know if the model...

Vuong test for comparing R-squared]]>

I saw the standard deviation calculation using within/between option in minitab tool,but I need to know the logic or fomula to drive it. I have to implement the same logic somewhere. Can any one explain this with data.

Thanks]]>

Im a student pyhsiotherapy and I have a limited knowledge of statistics! For my thesis I tested a lot of healty people (Control group) and people with Chronic low back pain (CLBP). I tested both groups on Reaction speed (seconds) and Accuracy (in percentages) of answers via a left right discrimination task. The data I obtained doing this test consists of 4 outputs (Left answers speed (seconds), right answers speed (seconds), left answer accuracy (percentage) and right answer...

Wich Test to Run for my data? student]]>

1. Is the R message *refitting model(s) with ML (instead of REML)* of any significance?

2. Comparing the 2 models using anova - have I done this...

Comparing mixed models]]>

Anybody have a common experience?]]>

I am comparing two discrete variables (where the values can be one and zero only) with a third one using chi square test and Cohen d for the effect size. In my comparison, I found that my Cohen d was greater than one, with a significant p-value. I searched the web and found a vague post that said that this indicate that the difference between the means in this case is larger than the standard deviation. But how can I report such result? Is it valid? Does that mean that the effect is...

Cohen d greater than one]]>

A-I have 1 categorical DV (2 level).

B-I have 1 categorical covariate (2 level) programmed as a categorical variable in the "Categorical" options in he regression window. That "indicator" and "Reference Category" stuff, which I'm not exactly sure how to work. I left it as "indicator" and "last."

C- I have 1 continuous fixed factor, which is really what I want to present. I want to present the relationship between this...

Binary Logistic Regression Questions]]>

So, the presence of agents A and B were determined in all subjects of the representative sample (n of aprox. 110). Also, A and B may be present in the same...

How do I compare 2 proportions (infection with agent A vs B) from the same sample?]]>

My thought process is to use a One-Way Anova as theres more than two categories for social status. Is this correct?

How do I determine if it is a normal distribution so that One-Way Anova is appropriate? And if not a normal distribution would I use Kruskal-Wallis?

I essentially need to determine any differences and give CI intervals for the differences. I'm not sure how I...

Which statistical test is appropriate?]]>

Large sample size but lots of missing data for ONE co-variate]]>

Estimating the age of labor market entry]]>

Looking into the model details, all the variables' p-values are higher than 0.05, and their coefficients are negative.

I thought this model would fail predicting properly, but the prediction score F2 particulary was actually higher than 0.93.

And I'm just wondering how these outcomes(p-values and prediction result) relate to each other.

I'd like to know if the model is worth or not.

Thanks.]]>

The dataset itself is rather complex, but attached is an excel file screenshot with a simplified tables demonstrating what I think is the problem. Would be grateful for a confirmation...

is regression analysis possible for this dataset?]]>

I am very new to regression and statistics and trying solve some questions where i have data and need to build a regression model, i am struggling with to get right dummy variable and also the R2 value is very low, so i am trying to find better option for correct model. I dont want to post files online.

Any help would be very grateful.]]>

I am looking at predictor variables (scores on partner perception measures) on a criterion variable (relationship satisfaction), in order to see how scores on multiple measures predict the participants overall relationship satisfaction. I believe that a multiple regression is the best statistical method to do this ( but I'm open to suggestions). The challenge I'm facing is that I'm looking at multiple populations, (differing age ranges, gender, races). In order to compare these...

Multiple Regression with Multiple Groups]]>

When arriving at the table, the sighted person sees that in pockets 0 32 15 19 4 21 2 25 17 34 6 27 there are particles that could obstruct the entry of the ball, the blind man does not see that.

The 2 players decide to play and write down what happened in the roulette. The blind man will play a dozen, the 1st dozen. The other player would also play 12 numbers, but making guesses he would play the next adjacent 6 numbers...

Bayes in roulette?]]>

I understand that a variable transformed into a normal distribution by taking the log of it has a lognormal distribution.

I thought that the pdf of this log transformed variable is , but looking at Wikipedia, this is the pdf of the lognormal distiribution. I am very confused and would really appreciate an explanation.]]>

Also, any answers that make use of R software are fine, I don't have access to anything such as Minitab, SPSS, or other packages though.

Here's a link to the formatted LaTeX : http://mathb.in/32195

If there's anything I can do to improve the post please let me know

Thank you...

Demonstrating that MAP -> MLE, Bayes]]>

I have two groups of the spine: normative (n=8) and diseased (n=10) (unpaired)

each spine has five levels, (L=1,2,3,4,5)

So while those spines were growing I have measured 4 different types of heights (Right, Left, Anterior and Posterior) for each level: 1,2,3,4,5. those measurements were taken at four-time points for each spine (time in weeks): 7,11,14 and 28

I want to study the following:

1. The effect of level and time point on those four height measurements...

What tests should I use for my statistical analyses]]>

A = player who is attacking

D = player...

Probability and risk board game]]>

1) I have a task to design a hypothesis testing using a case study, I have designed 5 null hypothesis test using independent variables for the dependent variable, in the absence of data from the survey, let's say assume all 5 null hypothesis is false (p<0.5), hence, a type 2 error. can anyone suggest how I can present the design and what method is best to test for bias and error? using SPSS

for example, 1) Hypothesis 1 (H01) state is there is no significant relationship between...

Multiple hypothesis testing and longitudinal method.]]>

I need to work out how to calculate passing intensity in football. One of the studies used the following formula:

However, I can't get the value that the authors got which is . This is Barcelona FC passing intensity. The total number of passes Barcelona performed in that season was 26613, which is on average 700 passes per game. Average percentage of ball possession of Barcelona that season was 65%.

What am I missing?

Quote from...

How did they calculate this?]]>

How can I redo the first version to the version with 0-1.0 axes?]]>

In Life

Some mock me for doing statistics

Some loathe me and statistics

Some don’t understand what statistics are

Why is it that statistics

Put a calm smile on my face?

Because of statistics I can solve the deepest mysteries

Because of statistics I will not be lonely again, playing in the data

Because of statistics I can rearrange the stars in the skies above

(by Chinese statistician Wang Jiaowei [translated],

The...

Statistics Poetry]]>

I have one independent variable (categorical) and want to determine its effect on two separate dependent variables. I know I could use MANOVA for this.

But what do I use if I want to determine the effect of an independent variable on two dependent variables and see whether it's stronger for females than for males? Two-way MANOVA?

(Basically if the effect of scoring above a cutoff on the IV has a stronger effect on both DVs for...

One IV, two DVs, across male/female. What could I use?]]>

I have 7 predictor variables I am considering putting into the model with correlation ranging -0.2 to .65 (I have heard it is okay to put features with low correlation to the response variable).

Now that I have these 7 predictor variables how do I know which ones to actually put. I am cross-validating, so would I just choose the combination that minimizes the error for when I predict on the test set?]]>

I am looking for suggestions for a seasonal time series. Ideally with at least four years (season cycles). I am soliciting suggestions for novel sets, not just the typical ones published in textbooks our used as online examples. Perhaps something current or perhaps esoteric.

Thanks,

hlsmith]]>

The survey produces equal-probability...

Why is there a difference in the confidence intervals calculated by SPSS compared to SAS and Epi-Info 7?]]>

There were 40 chess matches at the World Chess Championships. If we assume that the average attendance for all those games was 750 spectators:

What is the maximum number of games in which there could have been at least 1,500 spectators if the standard deviation of the attendance was 250?

I can plot the data, no problem. I can find the probability, no problem. What I can't seem to find out is *how* to figure the maximum number of games that could have 1,500...

Help finding the maximum number of instances.]]>

In this biological example, I am concerned with a mutant moss line that we hypothesized to have a higher cell count in moss filaments. I could not find evidence for a difference, though. A Null-hypothesis, using the t-test had to be maintained.

Now, I wonder how I would do statistical calculations with the Null-hypothesis of a set difference of for example a 10% difference. I want to know how valid my experiment...

Calculating type I error on the basis of Null-hypothesis: true count differs by 10%]]>

For my masterthesis I want to test the following model.

The effect of transformational leadership on learning motivation. Mediators are the three basal needs of the selfdetermination theory. So there are multiple mediations. These mediations are moderated by perceived workload.

Is it possible to test this model? Somebody who can help me out?

Kind Regards

Rik]]>

Hopefully someone can help me!

The problem:

I had participants do a test of knowledge, then use an educational intervention, take the same knowledge test straight afterwards, and then again 3 months later to test retention of knowledge. These participants also did a test of dexterity as that might affect how they learn from the intervention. I'm looking at whether the condition (type of intervention) affects the change in knowledge scores over time, and whether dexterity is a...

Mixed ANCOVA- significant covariate, insignificant between subj interaction!]]>

I have run a 3-way ANOVA and although I don't get a 3-way interaction, I do get two significant 2-way interactions (AxB) and (AxC). What should I do next to correctly interpret this result? How can I interpret that A interacts with B and A interacts with C, but no AxBxC interaction?]]>