I have collected data on offenders’ number of offences (0,1,2,3,4,5) (DV) in the previous year in different correction centres (level 2 as site) and thought about using multilevel Poisson regression (e.g., GLMER in R) but a preliminary result showed that the data were overdispersed. I tried re-grouping the DV data into a binary variable (0 vs. 1+) and using binary logistic regression model, and...

Logistic or Poisson regression?]]>

I'm a rookie in quantitative data analysis. I'm working on a survey of student responses across a number of schools. There are about 8 questions, and in the data there are YES's NO's but also quite few item non-responses dotted about. (I'm pretty sure it was a box for YES and NO, so some didn't cross either).

I'm doing some volunteer impact research and so I want to choose a defensible methodology to deal with item non-responses, but ideally I would choose a methodology that...

Item non-response]]>

I tried to calculate the minimum sample size for multiple linear regression.

I tried to check the sample size for predictors=4, effect size f=0.2/d=0.2, sig.level =0.05, power=0.8

1. When I checked the power of the entire model (F power) n=304

2. When I checked the power of one coefficient (t power) n=198

2. When I checked the power of one coefficient with Bonferroni correction(t power) n=281 (sig.level =0.05/4)

I probably doing something wrong as I get a smaller sample size when...

Minimum Sample size for multiple linear regression]]>

today I was doing a chi sq that resulted to be significant (p<0.05), but when I plotted the residuals they where all >1.96 or <-1.96.

I'm going to check the data again since I worry there might be something wrong in my file but I was just wondering if this is a possible scenario and if so how would you interpret the residuals?]]>

Any clues? Cheers, kat]]>

There is no statistically significant relationship between fasting and weight loss.

1 The chart (see way below) is a visual representation of my data. The circled points indicate a prolonged period of fasting and shows a downward trend in weight (i.e. weight loss occurred) during these periods.

...Which correlation coefficient is best suited to dichotomous variables (and why do my results feel intutiteivly wrong)]]>

I'll start with an article about how we share our data:

http://gigaom.com/2014/01/18/you-dont-want-your-privacy-disney-and-the-meat-space-data-race/]]>

Total 619 participants were given 4 types of test and then later on, based on their scores, were categorised as pass, clinical or double invalid. Can these data be used for statistical analysis? If so, can you suggest which test to use?

We want to know if scores from 4 different types of test can predict the outcome (pass, clinical or double invalid).

Thanks in advance for your help!

Regards,

Marianne]]>

a. There are 2 groups, an experimental group (n = 21) and a control group (n = 22).

b. There are 7 dependent variables, each with its own measure. Some of the DV's are related to one another: a) there are 2 measure of mental shift/attention, b) 2 measures of working memory, c) 2 measures of fluid processing, and d)...

Please help settle a disagreement, One-Way vs. Repeated Measures ANOVA]]>

My supervisor provided me with a dataset of which I am computing the variables. In the questionnaire, items were provided with a 7-point Likert-scale (1 = fully disagree; 7 = fully agree).

In my data set, all DV value-labels are set up as below. However, the value labels seem strange to me. For instance, value "2" is skipped.

Should I makes all value-labels equal (1=1; 2=2; 3=3, 4=4; 5=5; 6=6; 7=7)? Or is this a normal way of labeling?

Value 1 = Label "Fully disagree"

Value 3 =...

Compute Likert-Scale Measures]]>

I'm quite beginner in this field but now my research requires some methodology and I thought to create a topic, maybe somebody had the similar issue before.

I have some data regarding to health-related features, including:

- BMI (scale)

- Current diseases (categorical)

- Physical activity (scale, how long the participant does sport in a week, in hours)

- Tobacco use (scale, how often the participant smokes in a day)

- Alcohol use (scale, consumed alcoholic beverages in the past...

Clustering of behavior related data]]>

class Gaussian(BaseKernel):

def _compute_weights(self):

if not self.fix_boundary:

return(1.)

weights = np.zeros(self.data.shape[0])

for i,d in enumerate(self.data):

weights

return(weights[:,None])

def __call__(self, x_test):

distances = x_test[None,:] - self.data[:,None]

pdfs =...

Gaussian kernel density weight question (in Python)]]>

Methods

Fixed-effect model (state fixed effect):

Y...

Fixed effects regression]]>

I am new in this forum. I am a french post-doc in marine ecology and I am especially interested in trophic relationships.

I am currently analyzing time series. I have to admit that time series are definitely one of my strongest Achilles heels, I am actually afraid of them

Anyway, lets go to the point. My question is the following: How to test that standard deviation (sd) change over the time in a time serie.

Lets take an example. one investigated the depth...

Test temporal change in standard deviation]]>

First post here. I was trying to use the life tables option under survival analysis in the spss. Somehow, it shows me only scale variables and none of the nominal variables! Which is surprising as the Status variable is nominal. I checked the coding in the variables section and all looks well and all the nominals show up in other analyses that i tried. ]]>

I prefer to use excel or SPSS, but I can also download R or python if necessary. Thanks in regards.]]>

Thanks.

Which field of statistics does this fall under? I am trying to learn this.]]>

With the Patriots being cruelly eliminated from the playoffs, much to the delight of others, at least I have my numbers to watch and provide entertainment.

The nonlinear odds-to-probability derivations for the remaining non-Patriots teams were determined for winning the AFC and NFC Championship from current odds...

NFL postseason probabilities]]>

I'm struggling with finding an appropriate test for analyzing if responses are different based on certain properties.

In detail, participants had to recognize differences in images. Each participant received multiple images and in each image multiple differences were hidden. Each difference has certain properties and we would like to analyze if differences were recognized or not based on the properties of the differences. I was thinking of binomial logistic regression with the...

Choice of Test (Responses based on Properties)]]>

The second column pertains to the number of

1. Ordinary One-Way ANOVA

2. One Way ANOVA with Repeated Measures...

What Statistical Treatment can I use in this type of data?]]>

The Coefficient value for Hours Field is given 1.5046...

Would like to know Derivation of Coefficient for Below Dataset]]>

The Chebyshev empirical rule used for a normal variable, says that :

a) Approximately 90% of the values in the interval x+3s

b) Approximately 5% of the values are in the ... Interval

c) Approximately 95% of the z-values are in the Interval -2 and 2

d) Approximately 68% of the values are outside the interval -3 and 3]]>

I am new on this forum and completely new to stata. PROJECT FOR MONEY

Nevertheless, I am supposed to prepare a small project about alcohol consumption (in a couple countries - any) based on a couple variables like sex, type of alcohol, country, tax, GDP, etc.

The project should consist of the stata database, charts and tables, initial data analysis (continuous variables, unusual observations, descrete variables) and regression results (diagnostic test, robust regression).

Therefore I...

Stata project JOB CASH WORK]]>

30 medical students who have rated visibility of 40 brain anatomical structures (each structure has been rated on a Likert scale of 1-5, where 1 corresponds to "not visible" and 5- "clearly visible").

I am trying to figure out what will be the appropriate statistical test in this situation please to figure out the correlation among the ratings of the different students? I am not sure even if "correlation" will be the right test here, any advice for statistical analysis of...

What will be the right statistical approach for this design please?]]>

If the relationship between two variables is linear and positive:

a) the constant has a positive value, greater than 3.5

b) the coefficient of variation has a negative value

c) spearman rank correlation coefficient has a negative value close to zero

d) the kendall rank correlation coefficient has a positive value]]>

If the relationship between two variables is linear and positive:

a) the constant has a positive value, greater than 3.5

b) the coefficient of variation has a negative value

c) spearman rank correlation coefficient has a negative value close to zero

d) the kendall rank correlation coefficient has a positive value]]>

Based on the image attached above: If the p value is less than 0.05, does this mean the results show a significant influence of ecotype/salt conc. on rosette width. Or does it mean the null hypothesis can be accepted (with 95% certainly) if the p value is below 0.05?

It would also be appreciated if someone could tell me if my conclusion at the bottom of the image is correct.

I am using PAlaeontological STatistics (PAST).

Thanks in advance]]>

I am a bit of a novice of this so for give my ignorance.

Essentially i have two groups of data. One is for people with exon 19 mutations the other for those with exon 21 mutations.

Each group has different sample sizes with variables including overall survival etx. The overall survival data is a continuous variable.

My boss has asked my to calculate the means with confidence intervals of each group which I have been able to do.

She also wants p values to compare the OS between the 2...

Obtaining P values for 2 non- parametric continuous variables]]>

I was wondering if you could help me with this. I thought I'd be able to work this out but my stats knowledge is very jaded now.

If the mortality rate from an illness is 2% and I want to conduct a trial comparing treatment X with placebo, with a view to finding out whether treatment X reduces mortality from that illness--- how do I determine what sample size I will need to be able to say whether or not treatment X has a mortality benefit.

Thanks in advance.]]>

spearman coefficient is used to determine the connection between

a) 2 normally distributed non-numerical variables

b) a numerical and a non-numerical ordinal scaled variable

c) 2 binary variables

d) 2 non-numerical (one is ordinally scaled) variables (one does not know the distribution form)]]>

Month 1: the person ran a two sample t-test to compare an average

Month 2: the person ran a two sample t-test with updated treatment and control groups

Month 3: the person ran a two sample t-test with updated treatment and control groups

Month 4: etc.

I know there are...

Interim Analysis]]>

]]>

I am not sure if this is the right platform for my question. But I don't have many options!! I am working on a project where I am reading a bunch of sensor readings (numbers).

For example, the initial values I observe are 160, 161, 162 !!! (160 being the least and 162 being the max)

On the occurrence of an event, I observe 163, 164, 165!!! (163 being the least and 165 being the max)

On the occurrence of an event again, I observe 166, 167, 168!!! (166 being the least and 168...

Increasing the marginal difference between values]]>

Recent new member here. Have already learned some really useful things from this forum by searching through old threads, so I'm glad I stumbled across this site! I have a question of my own that I was hoping to get some help with.

We've run a clinical study. Prospective observational study looking at patients undergoing invasive electrophysiology study and ablation (tubes being stuck in a vein in a patient's leg, taken round to the heart, and cauterisation inside the heart) for...

Test for independent associations between patient characteristics and events]]>

I know that if the CIs of the two groups don't overlap at all, then they can be considered as significantly different. However if the CI do overlap, it does not necessarily mean that the two groups are not significantly difference.

Is there any way to determine if the two groups with overlaping CI are significantly difference or not...

Overlapping confidence intervals and p values]]>

I am a beginner in stats and admittedly not very good at it. As such I am a bit at a loss as to how to run the stats for my research project. I am doing a project with crayfish and observing their behaviors while interacting with several different trap types measures taken are the number of times each behavior was observed and for how long. I have 4 traps and each treatment has 5 trials. I need to calculate the average and standard deviation of the number and time of each...

Biostats Research Project Help]]>

it is a study with 4 groups + 1 control categorised by different stages of a disease. all 4 groups are given one kind of intervention (excluding the control).

at baseline, each group had 3 outcome measures eg (pain, distance and speed ) assessed and will be reevaluated at end of the 8 weeks of treatment.

what do i use?

t-test

anova

manova]]>

Im having some trouble solving this question..

I have 2 populations in which I have calculated the risck per patient-year for an specific event, in 2018 and 2019.

Now I have:

Event per patient-year:

Population 1

- 0.48 in 2018

- 0.32 in 2019

Population 2

- 0.61 in 2018

- 0.53 in 2019

What im trying to find is a way of proving that population 1 has a significant lower risk of events per patient-year than pop 2 (in each year and both years)

Is there a way of converting this into a p...

Obtaining P values for 2 variables]]>

Event A has on average a 5% chance to succeed when it triggers.

Event B has on average 15% chance to succeed when it triggers.

Event C has on average .2% chance to succeed when it triggers.

How...

How many events before statistical significance.]]>

I have a dataset of ~15,000 unique, nominal, categorical members. From that dataset, I have ~3,000 samples that are subsets of the overall dataset. Each sample has 100 unique members. A member's inclusion in a sample/subset is binary: either it is fully included or it is fully excluded. There may be overlap from one sample to the next; in fact, it is possible that multiple samples may be identical, but it's somewhat unlikely. Each sample is made...

Determining how similar different sets of data are]]>

Year Strokes in non-diabetics Strokes in diabetics

2002-2007 238/72243...

P value for trend]]>

While I was digging out the scientific literature on the calculation methods of percentile curves, I came up with a software called LMS (V 1.26) and tried to figure out what it is but found nothing useful. Because when I google "LMS" it returns a long list of another LMS (Learning Management System).

I need help with advice on where to start or how can I find the LMS (the statistical software)?

Does anyone have any experience with LMS software?

Thanks in advance for your contributions.]]>

for my thesis I am comparing 5 dental 3d intraoral scanner with a reference model. The study model is very similar to this study: https://ijcd.quintessenz.de/ijcd_2019_01_s0011.pdf

In this study they are using (P90-P10)/2 in the statistics wich is in my opinion the semiinterquartile range of P90-P10, if I am right.

I made 12 scans for each scanner. That makes 60 scans in total.

For each scan I have around 7000 values.

Now my Question is how do I calculate Precision and...

Precision/Trueness (P90-P10)/2]]>

i have a time series (let's say cash volume) designed like this:

Is there a statistical model I can use to estimate the stable part of my cash volume? In the figure the stable part is the sum of the dark blue and gray areas.

Thank you for your help,

Jim Castriotis]]>

I am aware that Stata 14 has a user written package called -punaf- to calculate Potential attributable fractions (PAF) as a post regresion procedure. Is there any way to calculate PIF. I couldnt find any clue from my search.

Thanks for sharing your insight.]]>