"elevated serum PTH concentration increased the risk of all-cause mortality (RR 1.19; 95% CI 1.08–1.30) but not for cardiovascular mortality (RR 1.26; 95% CI 0.96–1.66). Subgroup analyses indicated that cardiovascular mortality risk appeared to be more pronounced among men (RR 1.68; 95% CI 1.05–2.67)."...

i don't understand "Relative Risk" in this study]]>

It seems to me that a probability mass function is simply a probability measure applied to a discrete random variable.

Is that about right?]]>

- A porcine spine with three vertebral bodies (L1,L2,L3).
- The spine was scanned on three different imaging modalities (Modality A,B,C)
- On each of the modalities, different rings of fat were wrapped around the spine resulting in 5 different simulated sizes (size 1 to 5).
- For each vertebral body of each of the sizes of...

Repeated measurements with uneven sample size - which test is suited?]]>

A company I work at has a 'pay for' loyalty program. We track how many loyalty cards we sell daily. I was able to build a linear regression model based on NumberOfCardsSold, TrafficInStore, GrossRevenue for a specific day. R-square is 97.5%. All p-values are less than 0.05.

In order to drive loyalty card sales from time to time, we execute different card-related promotions and sometimes these promotions...

How can I enhance my linear regression model?]]>

I have conducted a "Principal Components Analysis" (PCA) in SPSS. I'm not 100% confident about my interpretation of the output.

Attached PDF provides an fundamental overview and includes SPSS table snapshots including comments and questions for each of the six (6) steps.

Would anyone be willing to review my comments and -- if required -- correct my statements about the outputs?

More importantly though I also included specific questions for steps 5, 6A, 6B, and 6C...

Need Assistance with Principal Component Analysis (PCA) Results in SPSS]]>

binomial standard deviation with weights]]>

When I run a multiple regression with both variables, the R^2 is above 90%, significance F is zero and both...

Interpreting coefficients in a multiple regression]]>

How should I...

Regression Question Regarding Wins]]>

Let’s say I have some participants who are administered a questionnaire at Baseline and then at 6, 12, 18 and 24 months (see table below).

The questionnaire has a total of 6 items across 2 scales (each scale has 3 items). One of the scales asks about physical functioning, the other about emotional...

Change over time in quality of life outcome]]>

I am currently undertaking a research project investigating the rates of violent assault across a 6-month period between 2019 and 2020 - looking at the latter in the scope of a COVID-19 period. The data is as such:

2019 – 62 assault TBIs

March: 12

April: 10

May: 12

June: 12

July: 5

August: 11

2020 – 34 assault TBIs

March: 9

April: 4

May: 6

June: 4

July: 4

August: 7

I am hoping to explore whether the difference in injury frequencies between these time frames is...

comparing frequencies between time frames - best choice of analysis?]]>

What is the smallest µ such, that H0 is rejected with a probability of 90%?

So, if I understand it correct, I have to find the sample mean X^- which satisfies that P(H0 reject|H0)<δ=0.05 and P(H0 reject)=0.9. I simply fail to...

Smallest µ such that H0 is rejected (hypothesis test, unknown mean)]]>

With South Carolina in the books -- for Biden, big-time -- and Super Tuesday on deck, let's revisit the implied probabilities:

Good ol' Joe has made a significant gain in implied probability -- up 5X since we last checked -- but Bernie remains the heavy favorite in this horse race to Milwaukee...

Election 2020]]>

I want to examine the effect of a treatment on an observation group with a Diff-in-Diff approach in a panel data setting in Stata. To avoid differences across subsamples I additionally using entropy balancing. Now, I have a methodical question.

I have already read some papers on this setting and noticed that the calculated weights of the pre-period are also used for the post-period. Why they not use the exact calculated weights in this case? I think in some ways this is data...

Entropy Balancing in Panel Data Setting]]>

My two top ones that I always watch but aren't particularly proud of because they're awful but I love them would be...

1) Hackers

2) Live Free or Die Hard (Honestly it's not a terrible movie but I feel like it is just so different from the first three Die Hards that I don't really even consider it a part of the original canon)

and then I'll list a bonus movie that I love and it really should be terrible but is honestly so good.... 21 Jump Street. It...

Guilty Pleasure Movies]]>

I think Telegram is at the top of my list so far but would love to hear what others here think and what you use.]]>

"Listen, I have seen that you did not...

Just for laughs!]]>

I am trying to superimpose the data on a scatterplot by time matching 1 and 2. In addition to time matching, I also have to match the Y-axis. I am trying to match 2 to 1 since 1 is calibrated and zeroed. There are thousands of data points so sample size should not be an issue.

I figured...

Acceptable average difference value for scientific literature?]]>

Thanks!]]>

I'd like to know given my win rate what is the average number of wins and points that I'm getting.]]>

Ik have a question about the interpretation of the estimates of fixed effects table in a multilevel analyses. In the analysis I compare 5 countrycluster (reference = cluster 1). The clusters are recoded in a manner that in the output cluster1=0 actually means cluster1=1. From the following output I can conclude that only cluster 2 and 4 are significant different from cluster 1 (p<.05). My question is, can I use the estimates of the insignificant clusters also to create a ranking about...

Interpretation multilevel]]>

I am studying Biostatistics now and my teacher giving me some exercise. However, it was so difficult for me to understand. Could anyone help me with this?

1)Three independent clinical trials study the efficacy of a new drug vs placebo.

Each trial has a probability of finding that the new drug is better than placebo = 0.8.

a) What is the probability all three trials will show the new drug is better than placebo?

b) What is the probability exactly one trial will show...

Help understanding and solve these exercises!]]>

I am new in this community. I hope you can help me out.

For my master thesis, I have a dataset of 6043 observations. This observations contain the spread differential (delta) of matched securities (I compare one corporate bond with a Green corporate bond of the same issuer)

What I want to investigate is, whether there is a significance in delta >= 0 (H_0) vs. delta < 0 (H_1)

Therefore I ran two tests on this datas.

1. one sample one tailed t-test

2. Wilcoxon test

The results...

t-test vs. Wilcoxon-test]]>

Actually, I don't know what this question wants to ask, does it want me to answer the probability of getting 32? Thanks!]]>

I have 2 independent variables and 1 dependent variable.

Thanks!]]>

I have two files, one is data for the population and one is the data for the sample.

All the participants in the sample exists in the population.

Can I put the population file and the sample file in one SPSS file even though the number of records in both are different?

Both files have key_number , and all the key_numbers in the sample are existing in the population.

Thank you

Sima]]>

Some background to my question:

I have titrated biomass samples which came from either a conventionally farmed field or one with special treatment to find their raw protein content. I want to be able to say whether biomass from conventionally farmed fields or specially treated sites has more protein.

I believe an ANOVA analysis is appropriate and, for that. If so, would it be a one-sided analysis...

ANOVA analysis of two site management types]]>

I'm doing using hierarchical Cluster Analysis with SPSS, for an ordinal variable (likert scale). The variable contains several statements.

Those statements are in rows not in columns (so the columns are the respondents are in columns). some of the participants did not answer all of the statements, so when I am running the analysis I get an error message, it seems that I need that all the answers will be completed. Can I fill the missing answers with the average of the respondents'...

Question about hierarchical Cluster Analysis]]>

I received some old data that I am now supposed to analyze, however, deciding for an appropriate statistical test turned out to be a little hard for me, so I could Need your help!

The data are basically from a 2x2 factorial design with Pre- and Posttest measures. It is an Intervention study (intervention vs placebo) that was conducted in a group of patients as well as in a group of healthy controls, so in theory there are 4 different groups (patient+intervention...

Questions concerning the analysis of my Data]]>

You have two coins, one that comes up heads 50% of the time and one that comes up heads 70% of the time. A friend of yours who wants to win some bets borrows what he thinks is your 70% coin to use on some unsuspecting people. Before using the coin, however, he decides to try it out on himself by tossing it 10 times. He decides that if heads come up 8 or more times out of 10, he will conclude that you really did give him the biased (70%) coin.

a) If, in fact...

solve part a and b .]]>

for the following question i was able to answer part A and B but i dont know how to answer part C

_______________________________________________________________

You have two coins, one that comes up heads 50% of the time and one that comes up heads 70% of the time. A friend of yours who wants to win some bets borrows what he thinks is your 70% coin to use on some unsuspecting people. Before using the coin, however, he decides to try it out on himself, by tossing it 10 times...

binomial/hypothesis tests]]>

could you help me solving this? Thanks a lot

What is the expected value and standard deviation of T?

T=a·b·ΔT

a=10+0.1ΔT (ppm/ºC)

b=N(6,0.2) m

ΔT=N(15,4) ºC]]>

I am a student currently working on analyzing data from an oddball experiment. We have 30 participants who went through two conditions (I will call them condition A and B) two times each. The order of the conditions was counterbalanced, so each participant would either do ABAB or BABA. In each condition (taken together across blocks), we got approximately 95 reaction times (RTs) from "standard" stimuli and 95 RTs from "odd" or...

Methods for trimming reaction times]]>

However the survey will be very long if I include all items for everyone (~60 minutes).

I've read about split questionnaire designs where you give a different subset of items to random groups of respondents so that they could have lets say half the questions but where across the respondents you get data for all items. Then you impute the 'planned missing data'; e.g. Rhemtulla, M...

Using split questionnaire design when validating measures]]>

The issue I am having is that I want to a t.test but after trying to run a t.test and getting error messages that i am using non-integer data, I think my data might not be properly arranged. I have attached a picture of my data table.

I want to know if the land management style ("Management") which is either conventional (KONV) or at reduced intensity (VNP) results in the plants there having more protein ("Stickstoff_mg"...

t.test and organizing data]]>

For my PhD, I am analysing the results of a survey with n=232.

The survey asked the participants about:

- their previous experience with an activity (yes/no)

- how many people did they know related to the activity (normalized to 0-100)

- their future interest in the activity after a measure is introduced (normalized 0-100)

I would like to analyse using bayes or t-tests if:

- the previous experience is related to the amount of people they knew related to the activity

- the previous...

paired vs independent, which one]]>

I have a basic question about factor analysis. From what I can understand, if different people look at the same data and factor analyze it (even with the same extraction method and rotation) they can come to different conclusions, based on certain factor loading cut offs and communality values?

I have done a factor analysis and have reduced my data to two factors, where all the items load reasonably well between the two factors, however, the communalities for two items are below...

Basic exploratory factor analysis question]]>

I need help with the following exercise. I don´t know how to solve it. Thanks a lot.

X=0.7Z

Y=1.7 + 0.4Z

μz=9 σz=3

E[(x-μx)·(y-μy)] ?]]>

Does anyone know packages or functions on R with which you can do block randomization with allocation ratio 3:1?]]>

I would like to ask about the maximum sampling error in stratified sampling

Suppose I have the following sample size and population in a survey:

Would like to enquire that:

Is the sampling error formula below appropriate, where n is sample size and N is population

I found the formula from this link -> https://www.educba.com/sampling-error-formula/

Thanks ! ]]>

b) When comparing the responses of psychologists in the questionnaire to a) the general population and b) another job category...

Sampling and design of study]]>

I would like to ask your help on the decision about the best methodology to determine the sample size to conduct an observational study.

This is a study to be carried out by a pharmaceutical company in which it is intended to characterize all combinations of drugs used before, during and after the administration of the drug of interest.

The patients observed are cancer patients with advanced stages of the disease and therefore frequently change drugs.

There is a great...

Sample size determination]]>

Does excel have an easy way to import excel files and do ODS graphing? I am trying to find the most automated way to do graphing I can find.]]>

Multi-objective optimization-selection of decision variables]]>

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]]>

Bayesian proxy to Huber-White Estimators]]>

This is my first time on this forum … thank you for accepting me!

I have run a Quade's rank analysis of covariance (Quade, 1967) using SPSS.

The reason I did not use a straight ANCOVA was because three of the five assumptions underpinning parametric ANCOVA were not confirmed in my data. As the non-parametric method (Quade's) identifies, you are running the ANOVA part of the ANCOVA analysis on the rank-ordered dependent variable with the residuals saved in the OLS regression...

Non-parametric methods]]>