The expected value of a random variable; or a location measure for a sample.

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5
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2answers
482 views

Reporting Results of Mann-Whitney U Test - Means vs Medians

I had a question yesterday that I got a bunch of great responses on. I have, hopefully, a quicker question here. There is a debate in the literature regarding reporting means vs medians in a ...
1
vote
1answer
247 views

2 discrete distributions with equal mean and variance

I need to compute 2 discrete distributions with equal mean and variance. One should be a distribution taking values x and y and the other one taking values z, 0, and y. The probabilities should take ...
8
votes
1answer
781 views

Which converges faster, mean or median?

If I draw i.i.d. variables from N(0,1), will the mean or the median converge faster? How much faster? To be more specific, let $x_1, x_2, \ldots $ be a sequence of i.i.d. variables drawn from ...
4
votes
2answers
198 views

How to properly state the average of a discrete number in a report?

I'm wording a report on the averages of a discrete variable, and am trying to get the most appropriate sounding wording. Consider the able below: ...
8
votes
1answer
2k views

Displaying Ordinal Data - Means, Medians, and Mean Ranks

Thanks in advance for any help. I have some ordinal data that is not normally distributed, so I decided to do non-parametric testing using the Mann-Whitney U Test. I am looking at differences ...
-2
votes
1answer
181 views

Calculating mean and variance of normal distribution restricted to interval

If one set a lower and an upper limit on the normal density, is it statistically valid to calculate the mean and Standard deviation of that normal variate. If yes, how can we do that in R? In a more ...
1
vote
0answers
46 views

Generate discrete distributions with same mean and variance

I have a question concerning mean-variance analysis. I need to compute 2 discrete distributions with equal mean and variance. One should be a distribution taking values x and y and the other one ...
4
votes
1answer
31 views

Is this method of arriving at a statistic valid?

The following is an excerpt from an article about gender bias : Overall, 34 per cent of respondents readily admitted that their family preferred having more boys. Given the sensitive nature of ...
2
votes
2answers
87 views

Mean Preserving PDF Spreading

I have a histogram representing the PDF of an unknown discrete RV. The histogram is asymmetrical. To be clear, all I have is the histogram. Is there a known way to increase/decrease the variance of ...
2
votes
0answers
64 views

Mulitvariate normal truncated conditional expectation

There is three-variable multivariate normal distribution. Denote 3 variables with $X_1$, $X_2$, $X_3$. Let $\mu_i$ be means, and $\sigma_i^2$ variances of respective variables, and let $\Sigma$ be ...
0
votes
1answer
76 views

Find new mean from Normal probability

I have a problem as follows. Life of tyres normally distributed for a specific make. mean=24,000 km and sd= 2500 km. Question is: As a result of improvements in manufacture, the length of life is ...
1
vote
1answer
125 views

Compare means of group with a mean of a subgroup

It is possible to compare a variable, for example age, between an entire group of patients and a subgroup of patients (a part of the entire group)?
5
votes
2answers
1k views

Arithmetic or geometric mean to calculate an annual average price index?

I have monthly indices (Consumer Price Indices for 12 months) for a set of countries. I want to calculate the annual average for each country in order to have an average Consumer Price Index for a ...
1
vote
1answer
52 views

Comparison of two means within the same group

I created a pretest before my main study. The goal of the pretest is to find two brands that are equal in terms of liking and familiarity. I computed the variables in SPSS and I was wondering if I ...
1
vote
0answers
37 views

Should I use arithmetic or geometric mean here?

So I have monthly indices (Consumer Price Indices for 12 months) for a given country. I want to calculate the annual average for each country in order to have an average Consumer Price Index for a ...
1
vote
0answers
26 views

Suitable model for predicting mean output over time

I have 3 years of yearly historic data on the results of a harvest (of truffles) from multiple different areas involving multiple individuals harvesting in each area. The dataset contains: name of ...
2
votes
1answer
369 views

Can covariance be derived from means and variances?

In treatment studies it is common to report multiple outcome measures from the same subjects. The treatment effects on these outcomes are typically correlated so this should be taken into account ...
1
vote
0answers
38 views

Relationship between mean and variance not removed after data transformation?

I am a student and I am doing a research where I have a trait (lets say cow weight in kilograms) that presents a relationship between mean and variance. I also have a factor that is country/year ...
-2
votes
1answer
57 views

Is the mean smaller than the median

The mean and the median selling prices of single-family homes were reported to be \$163,900 and \$210,900. The report was not clear about which was which. \$163,900 is the mean and \$210,900 is the ...
4
votes
2answers
2k views

Finding the Mean and Variance from PDF

A random variable $n$ can be represented by its PDF $$p(n) = \frac{(\theta - 1) y^{\theta-1} n}{ (n^2 + y^2)^{(\theta+1)/2}}.$$ $\theta$ is a positive integer and $y$ is a positive parameter. If ...
0
votes
0answers
206 views

Bootstrapping with standard deviation, mean and autocorrelation

I found in the matlab examples a way to use mean and sd for bootstrapping: ...
1
vote
2answers
71 views

Will the mean of a set of means always be the same as the mean obtained from the entire set of raw data?

If I have calculated the mean for 4 data sets (which do have different sample sizes), can I then obtain an "overall mean" by calculating the "mean of the means"? If yes, will this "mean of the means" ...
3
votes
3answers
498 views

The probability of a random variable being larger than a sequence of random values

Suppose we have a fixed, known, $n$, and each $x_1 \ldots x_n$ is a random number generated uniformly over $[0,1]$. What is the probability that $x_n$ is the largest value in the sequence?
0
votes
0answers
32 views

Do I need to use weighted means with the Wilcoxon signed rank test?

I have 22 patients. They have been measured pre and post treatment. There are 3 measurements per patient before treatment (pre baseline), and four measurements after treatment (post baseline). There ...
3
votes
2answers
150 views

Are there any other distributions whose shapes can be determined by just the mean and the standard deviation?

For the normal distribution, With the mean, and the standard deviation, we know the shape of the specific normal distribution - that is, the center of it and how spread out it is. I wonder if there ...
2
votes
2answers
458 views

Standardize non-normal predictors before performing binomial GLMM using mean and sd?

I am planning to predict a binomial variable (1/0, a used point by an animal or point available to an animal in its range) using several continuous, distance-based predictor variables (distance to ...
2
votes
0answers
61 views

If $Var[X]$ is much larger than $E[X]^2$ is E[X] an unreliable estimate?

My question is simple and I got this confusion when going through a Markov chains text book.If $Var[X]$ is much larger than $E[X]^2$ is $E[X]$ an unreliable estimate?
2
votes
1answer
678 views

Is my sample homogeneous? [closed]

I have a sample of 110 values between 0 and 180. These represent total degrees in an arc, and I want to be able to figure out whether or not I have a widely variable sample of arc sizes or if I have a ...
0
votes
0answers
58 views

Understanding correlation between Multiple Intelligences (MI) and digital technology competency

I appreciate all the help I can get to help me understand. The research reported here is about whether there is a correlation between multiple intelligences (MI) and digital technology competencies. ...
1
vote
0answers
20 views

Finding mean value from lines of regression [closed]

The two lines of regression are $8x-10y+66=0$,$40x-18y-214=0$. Find the mean values of $X$ and $Y$.
2
votes
3answers
253 views

Mean test of log-normal distibutions

I have two data sets, which are assumed to be log-normally distributed. How can I test whether their means are statistically different from each other? I guess I cannot use the 2-sample t-test, ...
4
votes
2answers
838 views

How does one find the mean of a sum of dependent variables?

I know that the mean of the sum of independent variables is the sum of the means of each independent variable. Does this apply to dependent variables as well? Thanks.
0
votes
0answers
89 views

Correcting data for mean but also variance

My data: I have data that range from 0 to 2 for numerous individuals. The scores are more or less normally distributed and vary continuously, but the scores are always between 0 at the minimum and 2 ...
4
votes
1answer
32 views

Different means with non-significant anova

I did an ANOVA test summary(aov(m$Y~m$type)) and I get a p-value of 0.067 i.e. the means are equal. But my means by type are these ...
10
votes
1answer
136 views

Show that if $X \sim Bin(n, p)$, then $E|X - np| \le \sqrt{npq}.$

Currently stuck on this, I know I should probably use the mean deviation of the binomial distribution but I can't figure it out.
2
votes
1answer
61 views

Quantitative Location Shifting Detection for Run-Sequence Plot

I am trying to complement a Run-Sequence Plot by some quantitative metric to validate that a dataset has a fixed location. Since the Run-Sequence Plot will be used in the early phases of Exploratory ...
1
vote
1answer
46 views

Quadratic mean convergence of a biased coin using conditional expectation

I'm a master's degree student and after a lot of research and some days trying I still can't get the answer for a question proposed by my Statistics professor. He asks to toss a coin with a random ...
3
votes
1answer
50 views

Is there a way to characterize the position of a point in a distribution that takes higher moments into account?

When summarizing a location in a distribution, we can take the mean into account by simply calculating $x-\mu$. We can take the standard deviation into account by calculating a Z score ...
3
votes
0answers
25 views

Test for participant subgroups in gradual means shift

In an experiment with 44 participants I have measured the response time for a set of stimuli, where the response could be a or b. The means of the two responses do not differ significantly (783.3 vs ...
3
votes
2answers
739 views

Difference between geometric and arithmetic mean

I still have problems to exactly understand the difference between geometric and arithmetic mean. I know that e.g. for returns, the arithmetic mean can be wrong (e.g. if I start with 100 $ and if my ...
1
vote
0answers
13 views

Constructing confidence intervals for mean of means, using standard errors [duplicate]

Is it possible to construct confidence intervals for a mean of weighted means using standard errors? I have 4 different weighted means ($p_t = \sum_{i=1}^{n} w_ip_i $ where $w_i$ is the respective ...
0
votes
0answers
193 views

The mean and standard deviation of an Kernel Density Estimation

[I have crossed posted this from StackOverflow. Not sure if this is allowed, but maybe there is a Python answer, or maybe there is a good stats answer] I have fitted a ...
2
votes
1answer
82 views

Significance of changes in mean values over time

I have 5 mean life satisfaction values for 5 different years; I have to find out if there is a significant relationship between the survey year and life satisfaction. How should I proceed? I was ...
6
votes
1answer
230 views

Is the mean of equal length subsets always equal to the mean of the set?

I've been fooling around with some numbers while learning R and would like to know if the following is generalizable. When I calculated the mean of numbers 1 through 100, I got this: ...
2
votes
2answers
110 views

Lognormal with negative mean?

I have a set of cycle time data for a processing counter. Since the cycle time is less than 1 minute, so the time taken are all less than 1 (ie 0.14m). I am trying to fit a distribution, but result ...
3
votes
2answers
222 views

Unsure how to find the MLE for this model

The question I am trying to answer is confusing me as I don't know where to start to find a likelihood estimation The Question $y_i = μ + e_i $ where the $e_i$ are independent variables ...
1
vote
0answers
160 views

Raw or Mean data; Anova or Regression

I would like to learn what is the correct way to approach analysis of this data. I have done some reading on the subject, but I still feel uncertain. Perhaps many approaches are valid, but simply ...
-3
votes
1answer
79 views

Which mean value should I use

I am to test the transformational shifts in three different directions for 3 different imaging techniques in a group of 30 patients. I am trying to prove one is not statistically different to the gold ...
1
vote
0answers
45 views

Mean of an interval censored random variable

It is likely that I am incorrect terminology here, but I am trying to compute a "mean" of an interval censored random variable. Here is an example where: 1. a random sample from the standard normal ...