The pearson tag has no wiki summary.
-3
votes
1answer
67 views
Why are log transforms used in measuring dose-time association?
Explain why log(dose) and log(time) are used to measure the association between dose and time instead of the actual values of dose and time.
1
vote
0answers
41 views
how to analyze necessary/sufficient relationship?
Good day!
I'm a second year psych grad student. From my fascination with formal logic, I wondered (just personal; not homework) about how to statistically establish necessary/sufficient ...
2
votes
1answer
59 views
Goodness of fit in a GLM with scaled deviance
On this page, I am interested in the section “goodness of fit”, which is near the bottom of the page and contains the table of deviance functions.
The author states that the scaled deviance, i.e. ...
2
votes
0answers
116 views
Why are $x$ and $x^2$ correlated?
I'm trying to understand why there tends to be correlation (as measured by the standard Pearson correlation coefficient) between $x$ and $x^2$ (for instance if $x$ is uniformly distributed).
It's my ...
0
votes
1answer
42 views
Calculating a correlation with yes/no answers?
How do you calculate a correlation, that similar to Spearman and Pearson forumlar when you are only comparing one variable (age) to answer given by yes and no. As ages goes up more likely to answer ...
0
votes
0answers
28 views
How to test if two populations are different with the x axis a time variable
I have two populations: Class A and Class B. Both populations have two variables: ...
0
votes
0answers
15 views
measure of correlation between arrays of two elements
How can i measure the correlation between two arrays if they are both long 2?
I tried with Pearson's correlation but it is always 1.0
Thanks
0
votes
0answers
17 views
Distribution analysis of values obtained in repeatable simulations
I have some computer simulation after running which I'm getting a fixed-length vector of results which take values from fixed small set of sequential integers (e.g. {1,2,3,4,5,6,7,8,9,10}). I need to ...
0
votes
0answers
47 views
Pearson Correlation Coefficient and gene expression matrix
This is a gene expression matrix. The first column are gene ids, the latter values are normalized gene expression values for controls (first 3 cols) and disease state (last 3 cols).
...
1
vote
3answers
183 views
How to interpret correlations with negative numbers in SPSS
I'm trying to establish a bivariate Pearson correlation between two groups of variables in SPSS, however one of the groups has positive decimal numbers and the other negative decimal numbers.
The ...
2
votes
1answer
59 views
Confused about comparison of Pearson coefficients
I am slightly confused on a paper I am reading. They have a table of calculated Pearson coefficients as shown here:
$$
\begin{array}
. & I & II & III\\
A + B & 0.8 & 0.65 & ...
1
vote
1answer
52 views
Pearson correlation for 'lumped' populations?
I'm currently using the Pearson (product-moment) correlation coefficient (PPCC) to look at the relationship between deprivation and healthcare usage in a population, but I think I've probably got this ...
0
votes
1answer
171 views
How to find exact p-value of Pearson $\chi^2$ test?
In a book I am reading, the author have calculated the Pearson $\chi^2$ statistic value as 11.50 and degree of freedom = 9. The p-value stated is 0.241. I look it up in a $\chi^2$ table but I only can ...
2
votes
1answer
78 views
Inference from linear regression slope and Pearson
Sorry if this has been asked before but I've already done quite a bit of work here and I feel like I'm quite close to an answer.
I am interested in testing whether the PHP function array_key_exists ...
1
vote
1answer
157 views
Estimate error of prediction from R-square
What I have:
a linear model $y=a_0+a_1x$ with given parameter estimates,
the number of values used for fitting the model,
the Pearson R² value.
I need to estimate errors of prediction. I don't see ...
1
vote
1answer
74 views
How to test for correlation with data that violates assumption of linearity and is not monotonic?
I have sampled 8 individuals (birds) from two regions. For each of these 16 individuals I have sampled 9 feathers that have each grown in sequential order (from 1 to 9). Next I have measure both ...
1
vote
1answer
451 views
Interpreting p-value significance from Pearson correlation
I used matlab corr() function to identify correlation of 236 samples. Pearson correlation is selected, and the output return r and p-value. Two sets of samples returned different r & p-value. May ...
0
votes
1answer
214 views
p-value for hypothesis test with given correlation, sample size
I'm writing a statistical tool in Java. Here I'm calculation pearson correlation values (r).
My next step is to validate if my correlation values are good enough to prove that my to variables are ...
2
votes
1answer
265 views
Assumptions of correlation coefficient
What are the assumptions for the proper use and interpretation of the Pearson's correlation coefficient?
How is $\DeclareMathOperator{\cov}{cov}\cov(X,Y)$ affected by (mild) deviations of linearity? ...
1
vote
0answers
79 views
On-line pearson calculator for students
I've been helping a friend with his stats homework. We are now working on Pearson's Correlation, whose calculation is done by a rigorously constructing a table of $x$, $y$, $(x_i-\overline{x})$, ...
0
votes
0answers
59 views
Use of cosine similarity on DGGE data
I am using the software package GelCompar to analyze some DGGE images of processed milk samples from a logitudinal study of 30 sheep.
The DGGE technique works by separating bacterial DNA in each milk ...
4
votes
1answer
147 views
False-error rate in a Pearson test, when approximation by a $\chi^2$ distribution is invalid?
The question arises in a cryptographic context involving a regulatory test of a physical source or random bits, with null hypothesis that they are independent and unbiased. $n$ samples of 4 bits are ...
0
votes
0answers
16 views
Correlation of a poll and another measure
I have this problem and I'd like some pointers to a "standard" method of solving this issue.
I have two time series, with points taken at the same time for each one of them; series A is a poll, of ...
5
votes
1answer
207 views
Does Pearson correlation require removal of bivariate or univariate outliers?
Does the Pearson's correlation estimator require no bivariate outliers, or no outliers in each of two individual vectors of data? The answer will impact on how I winsorize outliers before calculating ...
3
votes
0answers
59 views
What are the main different/alternative correlation estimators?
I'm looking to learn about the main/popular alternatives when it comes to estimating correlations that I've missed in the following list. The best answer will provide a reference (can be Wikipedia), a ...
1
vote
0answers
20 views
Different representations of the one-tailed/one-side hypothesis test [duplicate]
Possible Duplicate:
What hypothesis for A is better than B?
Consider the Pearson correlation estimate $r$. I want to do a hypothesis test.
$$\text{Option 1}$$
$H_0: \text{corr}(X,Y) \leq ...
0
votes
0answers
47 views
Why is $\rho$ used for both the population correlation and the Spearman estimate?
I am wondering why $\rho$ is used to denote the population correlation whereas it's also used to denote the Spearman correlation estimate. In this wikipedia article it's used to represent the Pearson ...
3
votes
1answer
474 views
Reporting coefficient of determination using Spearman's rho
I have two non-normally distributed variables (positively-skewed, exhibiting ceiling effects). I would like to calculate the correlation coefficient between these two variables. Due to the ...
3
votes
0answers
128 views
Mantel test vs. Pearson's correlation coefficient
Why is it correct not to measure the correlation between two distance matrices by calculating the Pearson's correlation coefficient between all distance pairs but to use the Mantel test instead?
...
-1
votes
1answer
187 views
Pearson correlation output in SPSS [closed]
In my research, I am trying to show the relationship between an IV and a DV.
As I compute the Pearson correlation through SPSS, it outputs a correlation matrix. This is not what I want. I need an ...
0
votes
1answer
176 views
Nonparametric Pearsons's r-value and p-value
Pearson's R Value shows the correlation of two arrays of real numbers. I would like to calculate an correlation value for text which is associated with numbers then a P value to judge the statistical ...
0
votes
0answers
31 views
What are Quasi correlations?
Someone know what quasi correlations are in a DCC GARCH output. I am familiar with the Pearson correlation, always between -1(perfect negative) and +1(perfect positive). In my output I have a quasi ...
1
vote
0answers
40 views
Simple similarity comparison over time
I've seen that Pearson's r is typically used for evaluation between non-experimental conditions. However, I've also seen Pearson's r used to indicate effect size - is this acceptable?
Is it a useful ...
1
vote
1answer
169 views
Sample size for Pearson correlation and the reverse coded items for correlation analysis?
Participants (N=14) filled in two questionnaires at two points of time, and I want to see the correlation between the variables.
Is this sample size sufficient?
Also, should I have reverse coded ...
0
votes
0answers
116 views
Scipy Spearman and Pearson [closed]
I had a quick question, I have a table of names with counts, think of it as a frequency distribution. I want to calculate the correlation between two tables, my question is do I need to transform the ...
0
votes
0answers
29 views
Pearson r Interpretation [duplicate]
Possible Duplicate:
Magnitude of a relationship
I have a set of data that has a Pearson correlation of .822 with sig. (1 tailed) of .001. I am not a statistics person but what exactly does ...
3
votes
1answer
247 views
Effect of log transform on Pearson correlation
Is there a generic answer as to how the log transform affects the Pearson correlation between two variables, i.e., is $\rho(\log(x),\log(y)) < \rho(x,y)$ always or the other way around and why?
1
vote
1answer
357 views
Validation of logistic regression - goodness of fit (pearson)
I have developed a scoring system using logistic regression. The score ranges between 0 and 6 (using integers) and predicts death. It does not use a conventional regression formula and thus I am not ...
1
vote
1answer
285 views
'Fixing' PearsonFitML to fit to a Pearson V distribution
I am using the pearsonFitML function in the PearsonDS package to do maximum likelihood estimation of parameters in R.
I am particularly interested in fitting Pearson Type 5 distributions to my data. ...
7
votes
2answers
2k views
Bonferroni correction with Pearson's correlation and linear regression
I am running stats on 5 IVs (5 personality traits, extroversion, agreeableness, conscientiousness, neuroticism, openness) against 3 DVs Attitude to PCT, Attitude to CBT, Attitude to PCT vs CBT. I also ...
3
votes
1answer
218 views
Why don't the results of testing $H_0 : \beta = 0$ and $H_0 : {\rm cor}(X,Y)=0$ agree?
I have 4 IVs in my model that directly effect the DV.
The results of the correlation & regression analyses showed that:
IV1&DV:
Pearson Correlation Coefficient: insignificant
Regression ...
5
votes
3answers
249 views
Basis of Pearson correlation coefficient
Pearson correlation coefficient is calculated using the formula $r = \frac{cov(X,Y)}{\sqrt{var(X)} \sqrt{var(Y)}}$. How does this formula contain the information that the two variates $X$ and $Y$ are ...
2
votes
0answers
197 views
Parametric or non-parametric tests? … or transformation?
I am using R to examine the relationship between two variables in a small data set (n=16).
My problem is that I'm not really sure how to handle the analysis (read: I'm in deeper waters than I've ...
1
vote
1answer
255 views
How is it correct to deduce significance level of Pearson's correlation from a table?
this is a rather elemental question, but any help would be appreciated anyway.
This webpage gives a method of finding the p-value of Pearson's correlation coefficient, using a table. However, the ...
1
vote
1answer
67 views
Characteristics of the surviving mice Experiment
Could someone help me sort through my experiment? I had a couple classes in statistics several years ago and I've let most of it slip.
Could someone provide statistical insight a better way to analyze ...
4
votes
2answers
540 views
What does it indicate when the Spearman correlation is a definite amount less than Pearson?
I have a bunch of related datasets. The pearson correlations between pairs of them are typically definitely larger than the spearman correlations. That suggests any correlation is linear, but one ...
1
vote
3answers
1k views
Taking correlation before or after log-transformation of variables
Is there a general principle on whether one should compute pearson correlation for two random variables X and Y before taking their log transform or after? Is there a procedure to test which is more ...
11
votes
2answers
7k views
What is the difference between doing linear regression on y with x versus x with y?
What is the difference between doing linear regression on y with x versus x with y?
I guess my confusion arises from the fact that the Pearson correlation coefficient of x and y is the same no matter ...
1
vote
3answers
613 views
Issues on computing Pearson correlation coefficient for two vectors
When computing the Pearson correlation coefficient between a vector $X = \{x_1,...,x_n\}$ and a vector $Y = \{y_1,...,y_n\}$, we need to compute it as
...
6
votes
5answers
415 views
What can I do beyond Pearson correlation?
While checking to see whether two variables were correlated, I observed that applying Pearson correlation yielded numbers as low as 0.1 indicating no correlation. Is there anything I can do to ...
