Linked Questions
14 questions linked to/from Error bars, linear regression and "standard deviation" for point
0
votes
2
answers
1k
views
R's lm(), get x when y is known [duplicate]
Here is some data and a logarithmic model:
df <- data.frame(
x = 1:8,
y = c(7.5,6,5.2,4.3,3.9,3.4,3.1,2.9)
)
model <- lm(y ~ log(x), data = df)
I am ...
- 1,588
2
votes
0
answers
148
views
Regression vs Calibration [duplicate]
When reading on the wikipedia page of Calibration they said :
" A reverse process to regression, where instead of a future dependent variable being predicted from known explanatory variables, a ...
- 867
15
votes
1
answer
2k
views
Errors-in-variables regression: is it valid to pool data from three sites?
I recently had a client come to me to do a bootstrap analysis because an FDA reviewer said that their errors-in-variables regression was invalid because when pooling data from sites the analysis ...
- 43.2k
2
votes
1
answer
376
views
What is bias in aerosol data?
I was reading this information related to aerosol, especially aerosol optical depth of the MISR and MODIS instruments. I didn't actually get what bias means in the context of the AOT retrievals of ...
- 6,847
4
votes
1
answer
642
views
linear model, given y, calculate the confidence interval for x
I fit the model y = a + b * x. And 95% CI for estimates of a and b are (a1, a2), (b1, b2), respectively.
If we have a new observation ...
- 171
0
votes
1
answer
653
views
How do I predict x values with confidence intervals from non-linear polynomial fit in R?
I have the following data.frame:
...
- 121
1
vote
0
answers
525
views
Error propagation through a calibration curve
Say I have a linear fit given y = ax + b. I'm given Δa and Δb as 95% confidence intervals.
I now have several measurements y1, y2, y3, ... etc, from which of course I can gather a mean, standard ...
1
vote
1
answer
524
views
Test for comparing x-intercepts of two linear regression
I would like to know how to compare, and then calculate significant differences, if any, between the x-intercepts of two regression lines. Practically, I should compare the values of x when y=0. I ...
- 11
1
vote
1
answer
149
views
What is the error of my regression? [closed]
I'm conducting a polynomial of a third degree upon a diode measurement where Amplification was measured against Voltage. It's a very exponential behavior.
However, I used the ...
- 3,493
1
vote
1
answer
179
views
Prediction Interval when independent variable has variance
Given an existing regression curve, how do I properly account for the known variance I have in some new value of X? If I had an observation $x_{new} = 700$ with a variance $\sigma_x^2 = 150$ then how ...
- 21
2
votes
0
answers
135
views
Regressing $x$ on $y$ for Count Data
Suppose I have data $x$ and $y$, where $x$ is a count and $y$ is continuous. I would like to predict $x$ from $y$.
Specifically, for my research question, $X$ can be viewed as being measured without ...
- 1,649
1
vote
1
answer
49
views
Estimate at which point a linear model hits a certain value (including probabilities)
I have a simple 1D set of datapoints with a trend, I want to estimate at which point $X_t$ (i.e., at which point in the future) the model will hit a certain threshold $Y_t$:
I can fit a trendline to ...
- 131
0
votes
0
answers
19
views
How to quantify prediction power?
I have data that is the result of measurements $f(x)$ at points $x$. These measurements fluctuate (call it noise), also differently for each $x$ so we have that $\sigma(x)$ are the fluctuations. By ...
- 229
0
votes
0
answers
20
views
Calculate when a time series will reach s specific value
I have a time series at day level granularity:
Date. Value
2023-10-01 78945
2023-10-02 78990
2023-10-03 79005
2023-10-04 78999
...
While there are some ...
- 101