Newest Questions
218,409 questions
2
votes
1
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26
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Sample size for (average) bioequivalence in R
The aim id to calculate the sample size for average bioequivalence trial.
I would like to replicate the below example from "Sample Size Calculations in Clinical Research" by Chow and Shao (...
- 121
2
votes
1
answer
49
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Do instrumental variables introduce problematic multicollinearity? If not, why not? If so, how is it deal with?
I've been confused about something. There are, among others, two important rules of linear regression modelling:
The independent variables should be uncorrelated with the residuals
Independent ...
- 223
0
votes
1
answer
69
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Please help me understand an example in a section 'Sampling Methods and Distributions'
It is one example in rudimentary statistics class.
A professor writes a statistics test and estimates that 90% of
test takers will complete the test in 1 hour or less. She gives the
test to a class ...
- 111
2
votes
1
answer
27
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Good introductory material on quasi-experiments?
I know about statistical tests and regression in general, and wanted to learn more about quasi-experimental design. What are some good introductory resources about that?
I'm looking for resources ...
1
vote
1
answer
27
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Which measure of central tendency should be used when the question asks for “on average” versus “typically”?
In an exam I came across the following problem:
A company manager recorded the number of employees’ cars already parked when they arrived over nine days:
...
- 347
0
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0
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19
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Why is Beta reported when it derived from partial correlations, as opposed to semi-partial correlations?
In a simple standard multiple regression, with variables A and B as the IVs and Z as the DV, the partial correlation between A and Z factors out variance due to B from both A and Z, whereas the semi-...
-4
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0
answers
25
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Statistical Significance in A/B Testing [closed]
Can someone explain the concept of statistical significance in the context of A/B testing?
-4
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0
answers
30
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Temporary Post for Testing [closed]
I'm conducting a hypothesis test to determine if a new teaching method is more effective than the traditional method. I've collected test scores from two groups of students, one using the new method ...
0
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0
answers
10
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Latent Transition Analysis (LTA) manual 3-step process non-positive definite
I am currently running an LTA in Mplus, specifically using the manual 3-step process to convert the LPA to LTA.
I saved the SVALUES from the longitudinal similarity tests (in this case, it is from the ...
-3
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0
answers
13
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Conditional formatting - Colour cell if separate tab has same email, within a certain date range [closed]
=COUNTIFS('TAB1'!$F$3:$F$10006,"B2", 'TAB1'!$B$3:$B$10006, ">5/5/2024")
This formula doesn't work for me. I tried it with the quotation marks removed, also.
TAB 2 has a list of ...
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1
vote
1
answer
34
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T-Test to view change in new users from website
New to stats and industry - I want to see if new users on a website changed as a result of an advertising campaign in a specific state. Could I run an independent t-test to see if the change in new ...
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4
votes
2
answers
58
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Coefficient of determination ($R^2$) for complex-valued models
For a model $f:\mathbb{R}\rightarrow\mathbb{R}$, the coefficient of determination is unambiguously defined by:
$$
R^2=1-\frac{\text{Unexplained variance}}{\text{Total variance}}=1-\frac{\sum_{k=1}^n\...
- 141
3
votes
1
answer
299
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How is it that a time series can autocorrelate with first lag but not the second? And conequence on linear regression
When I have a time series that I want to model as an autoregressive series, I express my value at time t as a linear combination of previous values:
$$y_t=\sum_{i=1}^p\theta_iy_{t-i}+e_t$$
Right, but ...
0
votes
0
answers
14
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Downscaling (changing time series scales) for moving average model on time series data
I have a moving average model which performs moving-average over time series. And I want to downscale it from daily data to hourly data. However, I am confused how can I do that?
For example, if my ...
- 203
0
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0
answers
24
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is there a way to do a repeated measures ANOVA with nested random effects in R?
Basically the title. I know the anova_test() from the rstatix package can do repeated measures and does have an inclusion for error, but I'm not sure if I'm doing it correctly and I'm not including ...
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