# Tagged Questions

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7k views

### Difference between standard error and standard deviation

I'm a beginner in statistics. I'm struggling to understand the difference between the standard error and the standard deviation. How are they different and why do you need to measure standard error? ...
4k views

### How should one interpret the comparison of means from different sample sizes?

Take the case of book ratings on a website. Book A is rated by 10,000 people with an average rating of 4.25 and the variance $\sigma = 0.5$. Similarly Book B is rated by 100 people and has a rating of ...
475 views

### Explain regression to 7 years old [closed]

Please give a clean, simple, explanatory answer that any 7 yr old can understand. You can also link to a regression guide that is very good and simple. Should be fully explanatory all the way ...
5k views

### How do I interpret the results of a Breusch–Pagan test?

In R I can perform a Breusch–Pagan test for heteroscedasticity using the ncvTest function of the ...
360 views

### How does regression analysis help one understand how the typical value of the dependent variable change?

regression analysis helps one understand how the typical value of the dependent variable changes... -- http://en.wikipedia.org/wiki/Regression_analysis What does this mean? What "typical ...
3k views

### What is a standard deviation?

What is a standard deviation, how is it calculated and what is its use in statistics?
1k views

### What do “endogeneity” and “exogeneity” mean substantively?

I understand that the basic definition of endogeneity is that $$X'\epsilon=0$$ is not satisfied, but what does this mean in a real world sense? I read the Wikipedia article, with the supply and ...
198 views

### Determining values of correction factor based on x bins in observed vs. actual data

I am trying to automate a problem I usually solve by hand. I have a sensor that collects data from the field. Every 6 months or so, I have to do a calibration on that sensor by collecting ...
1k views

### Can someone explain the concept of 'exchangeability'?

I see the concept of 'exchangeability' being used in different contexts (e.g., bayesian models) but I have never understood the term very well. What does this concept mean? Under what circumstances ...
139 views

### Frequentist ability to use observations

I'm not an expert in statistics, but I gather there is disagreement whether a "frequentist" or "Bayesian" interpretation of probability is the "right" one. From Wagenmakers et. al p. 183: Consider ...
2k views

### Yates continuity correction for 2 x 2 contingency tables

I would like to gather input from people in the field about the Yates continuity correction for 2 x 2 contingency tables. The Wikipedia article mentions it may adjust too far, and is thus only used in ...
864 views

### Question about independence assumption for ANOVA, t-test, and non-parametric tests

I'm a novice in statistics and I have some confusion about the assumption of independence for statistical tests. I searched the Internet and some information says that for the t-test, the ...
291 views

### Scale parameters — How do they work, why are they sometimes dropped?

I'm having difficulty wrapping my head around scale parameters. How exactly do they work? Why are they sometimes ignored? (in other words, when is it important to preserve them in a calculation?) ...
983 views

### Understanding a Quantile-Quantile Plot

I must have generated at least 5 Q-Q plots until now when trying to fit my data into a known distribution but I just noticed something that I could not understand. In the figure shown below, from what ...
498 views

### Proper ways to perform time series and ARIMA

Note that I do most of my analysis using R and Excel. Let's take this data set for example. I modified it as the data itself is proprietary: the years are also different: ...
297 views

### t-test that means are the same?

I think this is simple, and I am wrong-thinking it.... t-tests are used to test the null hypothesis that the means are equal; $H_0 : \beta_1 = \beta_2$, $H_1 : \beta_1 \neq \beta_2$ But I want to ...