Tagged Questions
0
votes
0answers
118 views
Which test to check statistical relationship betwen paired/unpaired data?
I have data that is in-between of "independent samples" and "paired samples". About 50% to 70% of observations are matched (paired) and the rest miss a pair. Which test should I use - chi-square ...
3
votes
2answers
429 views
How to get the expected counts when computing a chi-squared test?
I just have 1500 data points in excel. However, I want to do a chi squared test to prove if the data is normaly distributed.
My question is: How to calculate the expected range for such a large data ...
2
votes
3answers
134 views
How can I test the same categorical variable across two populations?
I have data that looks a little something like this:
ID Status
01 A
02 G
03 E
... ...
100 G
You get the idea, I ...
1
vote
1answer
71 views
Chi Square Testing - binary outcome analysis
I have formed a contingency table for my binary outcome experiment that has been discussed in my previous question : binary outcome testing
One of my hypothesis says that females are better at ...
2
votes
0answers
64 views
Chi square for logical vectors: 2 row contingency table or 1 row vector?
I want to determine the independence between groups of logical variables. For example, for three groups, I want to know if the number of females (versus males) differs between the groups. I'm ...
2
votes
2answers
71 views
Comparing contingency table distribution
I want to compare the distributions of $K$ contingency tables, where each table is $N \times M$.
To make things clearer, let's work on $K=M=N=2$.
Suppose I have a classical cases and controls test, ...
1
vote
0answers
27 views
Test to use to measure the association of half-deciles
I'm querying a large (100 million row + ) SQL Server database and doing some preliminary work on the correlation between visits to the emergency room and total healthcare costs. I ran a query and the ...
3
votes
1answer
145 views
Comparison of entropy and distribution of bytes in compressed/encrypted data
I have some question which occupies myself for a while.
The entropy test is often used to identify encrypted data. The entropy reaches its maximum when the bytes of the analyzed data are distributed ...
1
vote
0answers
57 views
significance test to use for multiple conversions in an A/B test
What is the proper way to measure significance in an A/B test, when a visitor can potentially "convert" more than once?
I understand a chi-square test or z-test are most often used for A/B testing, ...
-1
votes
2answers
114 views
Null hypothesis and $\chi^2$ test
Which null hypothesis can be tested by a $\chi^2$ test?
could you please write the description of the relevant null hypothesis or at least give an example.
Thank you.
2
votes
1answer
208 views
Test for multinomial distribution
I have a sample of animals and a categorical variable of $L$ behaviors $i=1,...L$. I computed the proportions of this sample corresponding to each behavior category $p_{i}$, $\sum p_{i}=1$.
Can I ...
1
vote
2answers
97 views
Independence test for values between 0 and 1
I want to compare a set of frequencies and determine the p-value of their dependence. One of them is the null distribution of frequencies and the other is the distribution that I want to test. The ...
2
votes
1answer
258 views
Appropriateness of K-S test and Kruskal-Wallis for assessing medical data set
I am analyzing some stats for a paper I am writing. I have statistics help available through my faculty but am not there for a couple of months so hoping you can help out.
n = 463, 2 patient groups( ...
1
vote
1answer
211 views
How to set the non-centrality parameter of the chi-squared distribution in terms of sample size for a power calculation
I am doing some problems on hypothesis tests on the variance, using a $\chi^2$ distribution. I need to find the power of the test, and I tried to write my own code in
R.
I don't know how to express ...
2
votes
0answers
190 views
Relation between reduced chi square and Akaike criterion
In choosing the best fit between different curves, supposing the errors are distributed normally, I can do the following things:
Calculate the reduced $\chi_r^2=\frac{\chi^2}{N_b-N_p}$, where $N_b$ ...
3
votes
1answer
130 views
Does there exist some sample size threshold for choosing between the chi-squared test and the exact binomial test?
I'd like to use the exact binomial test to analyze some data,
but the exact binomial test takes too much computation and is unnecessary when the sample size is larger because it can be approximated ...
1
vote
1answer
787 views
Chi square test on non-normal distributions
I'm a beginner in statistics and would like to understand one of the requirements for the chi-square test to work. It is that the random variable being measured has to follow a normal distribution.
...
0
votes
1answer
134 views
Chi^2 test for 2x2-contingency table using probabilities instead of count data
I would like to perform a $\chi^2$ hypotheses test for association based on a $2 \times 2$ contingency table. However, my contingency table
$\begin{tabular}{|c|c|}
a & b \\
c & d
...
3
votes
1answer
135 views
Am I using the wrong statistical test?
I am using $\chi^2$ to analyze a set of data gathered over 4 time periods. The two variables are independent--each 'event' is categorized as 'good' or 'bad'. We want to prove that the intervention ...
1
vote
1answer
120 views
Statistical analysis for rubric-based research
There are 26 participants who have participated in my research. Each participant treated with a lab module (Hands on Robotics Session). Now each participant will be evaluated using a rubric on scale ...
1
vote
2answers
150 views
When does a random test fail?
I must implement some Chi Square Test to test the randomness of "my" implementation, but I can't understand what this tests really say.
The tests are different but what I always do is: divide in ...
1
vote
0answers
70 views
Phi MOA, Chi-Square and Null Hypothesis, What can be learned?
In short, is there anything to be learned from performing a Phi measurement of association (MOA) on a Chi-Square test where it failed to reject the null hypothesis?
$$\phi = \sqrt{\chi^2/N}$$
where ...
0
votes
1answer
43 views
Appropriate test for difference in trials with varying calibration
Let's say I collect data from an experiment where for each measurement device, 5 trials are conducted at different temperatures. Each device is calibrated separately, and the 5 trial temperatures are ...
2
votes
1answer
533 views
Comparing two discrete distributions (with small cell counts)
I need to compare sample distributions with theoretical ones, which is typically done with a chi-squared test. The problem is that I have distributions where one or more cells have low values, and ...
1
vote
1answer
168 views
How to interpret results of a $\chi^2$ test of independence?
I've run a chi-square test of independence on a two-way table with two categories on the rows and four categories on the columns. My $p$-value is below my chosen $\alpha$, so I may conclude that the ...
2
votes
1answer
310 views
Testing the significance of differences in frequencies across treatments using $\chi^2$ test
I've run a small experiment and need to test the data by comparing the frequencies of different treatments, specifically, whether they are significantly different. I think the chi-squared test is ...
13
votes
2answers
10k views
Chi-Squared always a one-sided test?
A published article contains these 2 sentences:
"Moreover, misreporting may be caused by the application of incorrect rules or by a lack of knowledge of the statistical test. For example, the total ...
5
votes
0answers
145 views
Adjusting the p-value for adaptive sequential analysis (for chi square test)?
I wish to know what statistical literature is relevant for the following problem, and maybe even an idea on how to solve it.
Imagine the following problem:
We have 4 possible treatments for some ...
1
vote
1answer
113 views
What is the outline for the procedure of model selection, with different models based on likelihood functions?
I have two basic models $M_1$ and $M_2$. They each have a likelihood function;
$L_{M_1} = f(\mathbf{X}|\mathbf{\theta_1})$ and $L_{M_2} = f(\mathbf{X}|\mathbf{\theta_2})$ (here $\mathbf{X}$ is the ...
3
votes
0answers
104 views
Is there an error in this published Chi-squared table?
I am questionning the Chi-squared table given in 100 Statistical Tests (3rd Edition, 2006) by Gopal K. Kanji, reproduced in part below.
Specifically, I think the Two-sided and One-sided levels of ...
0
votes
1answer
382 views
Proper use and interpretation of chi-squared test
Please help me understanding basic features of chi-squared test for distribution comparison.
As far as I understand, if we draw two samples from the same distribution, and treat one sample as ...
2
votes
3answers
2k views
Can chi-square test be performed on data that does not have normal or gaussian distribution?
Can chi-square test be performed on data that does not have normal or gaussian distribution?
One of the chi-square tests I am performing results in percentage points less than the 12.59 (α=0.05, v=6) ...
2
votes
1answer
103 views
Chi square based measure for fairness?
I have some project categories $(PC_1, ... ,PC_n)$ and some institutions $(I_1, ..., I_n)$ and would like to determine how fairly projects are assigned to institutions and their project categories by ...
12
votes
2answers
2k views
Why does chi-square testing use the expected count as the standard deviation?
In $\chi^2$ testing, what's the basis for using the square root of the expected counts as the standard deviations (i.e. the expected counts as the variances) of each of the normal distributions? The ...
3
votes
3answers
237 views
Significance test of whether participants have more friends of the same sex
I've run into a simple problem - but no idea how to access it correctly.
I've 85 people asked concerning their social network; first example: how many friends do you have. Second, what gender is each ...
3
votes
5answers
3k views
Can chi square be used to compare proportions?
I've read that the chi square test is useful to see if a sample is significantly different from a set of expected values.
For example, here is a table of results of a survey regarding people's ...
3
votes
1answer
1k views
Statistical significance (chi squared) for percentages over 100%?
So, working in web analytics, it's common to use a chi-square test for A/B tests to test statistical significance. I often use a calculator like this: http://www.usereffect.com/split-test-calculator , ...
2
votes
1answer
304 views
Multiple comparisons on nested subsets of data
Suppose I am doing some experimental procedure on two treatment groups. The procedure has several stages, each of which may fail. Failure at any stage halts the experiment. If all stages are passed ...
