Science topic

Weights and Measures - Science topic

Measuring and weighing systems and processes.
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Hi,
We are currently exploring how to work with weights in R as preparation for an upcoming survey, but we have encountered some limitations. To test this, we are working with a subsample of the 11th wave of the European Social Survey, focusing on data from Austria and applying the post-stratified design weight ("pspwght").
Our main issue is that the survey package lacks implementation for some measurements, such as McDonald's Omega. Because of this, we proposed an alternative procedure in which the rows in the dataframe are replicated based on the rounded weights:
Experimental_sample <- Austria[rep(1:nrow(Austria), times = round(Austria$pspwght)), ]
The purpose of this approach is to use the "weighted dataset" and directly apply the omegafunction from the psychpackage. However, we are uncertain whether this procedure is correct. Are there any alternative methods for dealing with survey weights and measures like McDonald’s Omega? Additionally, we have noticed that this method is somewhat similar to how SPSS calculates weights and that it could potentially introduce bias, is this accurate?
We would greatly appreciate any insights, alternative solutions, or feedback to ensure we are using valid methods while working with weighted survey data. Thank you in advance!
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Do you need to weight to get internal consistency reliability?
It looks like you're weighting to get results representative of a population. Its not necessary, I think, to assess internal consistency reliability. I think the normal approach here would be to calculate omega on the unweighted scores and use the scale or subscale scores with weights in subsequent analyses.
Its possible weighting is part of the scale scores (but that's unsusual) and then I think you'd need to seek expert advice on the best way to handle that.
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Hi,
I use some official data form our national statistical office survey (N = 1350). I have one independent variable of 6 age classes and one dichotomous dependent variable (looking for health related information online 1-Yes, 0-No).
I use SPSS, Chi2 test to detect group differences.
CROSSTABS
/TABLES=IHIF BY AGECLS
/FORMAT=AVALUE TABLES
/STATISTICS=CHISQ
/CELLS=COUNT EXPECTED ROW COLUMN BPROP
/COUNT ROUND CELL.
I have a weight variable. So, when using weights, I get all classes to be statistically significant (attachment 1).
If I don't use weights none of the groups if significantly different from the other (attachment 1).
So, am I using the wrong test, should I just omit weights or is there some other issue with the data?
Thank you for your help.
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Dear Nor,
I am running a non parametric test because of the one dichotomous dependent variable. My "book" says:
The chi-square test of homogeneity is used to determine if a difference exists between the binomial proportions of three or more independent groups on a dichotomous dependent variable. It will let you determine whether the proportions are statistically significantly different in the different groups (i.e., whether the proportions in each group are equal in the population).
Kind regards
Mitja
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Dear all,
I am in the process of developing an energy behaviour maturity model for organisations in my PhD. So far, I have conducted expert interviews and focus groups on developing factors and maturity level descriptions (for 5 maturity levels against the factors). The structure of the findings so far is given below.
As the final step, I am going to develop the tool further as an assessment tool. Therefore, I am seeking ways of assigning weights for each main factor and sub-factor (Reason: The main factors/subfactors identified seem to have different impact levels for the energy behaviour maturity. Therefore, if I can assign weights that can be reflected in the results of the maturity assessments conduct using this model in the future)
Note: There are no subfactors for some of the main factors. Altogether, under the 3 Areas, 15 main factors and 5 subfactors are available. If required, the 3 areas can also be assigned with weights.
The structure of the current findings is as follows:
Area 1
  • Main factor 1.1
  • subfactor 1.1.1 ------------ Level 1 to Level 5 maturity descriptions against factors
Area 2
  • Main factor 2.1
  • subfactor 2.1.1 ------------ Level 1 to Level 5 maturity descriptions against factors
Area 3
  • Main factor 3.1
  • subfactor 3.1.1 ------------ Level 1 to Level 5 maturity descriptions against factors
I would be grateful if you could provide your thoughts on this matter.
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You may try with Fuzzy logic theory or multi-grade Fuzzy approach.
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Hello everybody,
I was wondering whether the formula of a geometric mean can be solved to determine the weights. More specifically:
- I have the weighted geometric mean of two values. I know the two values and the geom. mean.
- The sum of the weights is 2, so if w1 = 1, then w2 = 1.
Changing the formula of the weighted arithmetic mean was fairly easy so I am surprised why conventional tools such as the online Wolfram Alpha tool seem to fail, so I presume that I failed somewhere along the way.
I am looking forwards to your thoughts on this!
Lukas
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Thank you for your fast replies! This helped me a lot.
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The development of IT and information technologies increasingly affects economic processes taking place in various branches and sectors of contemporary developed and developing economies.
Information technology and advanced information processing are increasingly affecting people's lives and business ventures.
The current technological revolution, known as Industry 4.0, is determined by the development of the following technologies of advanced information processing: Big Data database technologies, cloud computing, machine learning, Internet of Things, artificial intelligence, Business Intelligence and other advanced data mining technologies.
In connection with the above, I would like to ask you:
How to measure the value added in the national economy resulting from the development of information and IT technologies?
Please reply
Best wishes
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Dear Tarandeep Anand, Reza Biria, Krishnan M S, Thank you very much for participating in this discussion and providing inspiring and informative answers to the above question: How to measure the value added in the national economy resulting from the development of information and IT technologies? Thank you very much for your inspiring, interesting and highly substantive answer.
Thank you very much and best regards,
Dariusz Prokopowicz
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Update
I have a scale (12 items)
I go to Analysis -> Scale -> Reliability analysis and get my Cronbach alpha (0,5)
BUT 2 of my items are «inverse». If I recode this two items as it was not inverse I get alpha=0.8
Am I right? I should recode this items before counting Cronbach alpha?
written earlier
I conducted a study (correlation plan).
I used (including) 2 psychological tests, which were adapted by another author according to all the rules.
And I run into problems:
Situation1 (solved)
My first test (14 items) has 2 subscales. In Ukrainian adaptation, the Cronbach alpha for the scales is 0.73 and 0.68. But I did my own research and counted Cronbach's alpha. 0.65 and 0.65 came out.
Question1: Should I count correlations with this test or, maybe, exclude this test from analysis?
Situation 2 (see update)
My second test is Zimbardo’s Time Perspective Inventory (56 items). In Ukrainian adaptation, four of five scales have Cronbach Alpha above 0.7. One scale is 0.65.
But in my research everything is ok only with 3 scales, they are higher than 0.7.
Two scales have a very low Cronbach Alpha: 0.55 and 0.49.
Question2: should I exclude this two low scales and count correlations with only that 3 scales which Cronbach Alpha more than 0,7?
PS: N=336 in my study
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No matter create or use Oleksandra Shatilova any measurement tool must be valid. And cronbach alpha's say nothing direct things about validity. When you handle with reverse questions, Cronbach's alpha must be rise. But it is not sufficient.
So i agree with Robert Trevethan 's advices
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Hello everyone, I want to understand the weights systems in the Bronze age in MiddleEast but what I don't get it, is the ratio of these weights and the basis for these ratios. like in the Mohenjo-Daro case, we have 2, 4, 8...1600 ratios.
so I want to know two things: 1. what is the basis for these ratios? is that just arbitrary numbers for divisions of weights or maybe it has equity for reaching these ratios?
and question 2. if in one site we got different ratios so what is the difference between Mesopotamian and Indus weight system? from my perception, it's just a difference between ratios in two civilizations just like the difference between ratios in one single site, a regular difference that not a big deal, so maybe there is no difference and we want just imagine there is!!!
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thank you very much for your answer. that was my problem, the basis of archaeological material for determining these values and ratios. now the divisions of each weights values by ratios is the lowest weight value.
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The "Convocation de la Conférence générale des poids et mesures (26e réunion)" held in Versailles, 13-16 novembre 2018, has revised the International System of Units.
In particular, the definition of the Kilogram in force since 1889 has been abrogated. In its place, effective from 20 May 2019, it is agreed that:
"the mass of the international prototype of the kilogram m(K) is equal to 1 kg within a relative standard uncertainty equal to that of the recommended value of h at the time this Resolution was adopted, namely 1.0 × 10–8 and that in the future its value will be
determined experimentally"
and
"The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10^(–34) when expressed in the unit J s [Joule•second], which is equal to kg m^2 s^(–1), where the metre and the second are defined in terms of c and Δν(Cs)."
Under these conditions, what exactly the new Kilo inherits from the old one?
What is the "relative standard uncertainty" referred to in Appendix 2?
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Thank you for these questions. I am a consultant to the BIPM, but the following answers are my own.
1. The new definition of the kilogram was possible because the Planck constant h had recently been measured to sufficiently high accuracy in terms of the old definition of the kilogram (dating from 1889). According to the new definition of the kilogram, the former experimental value of the Planck constant now has no uncertainty. The fixed value of the Planck constant therefore defines the kilogram (the definitions of the second and the metre are also needed, but these have not been changed). What happens to the previous relative uncertainty of h? It now falls on m(K), the mass of the cylinder known is the International Prototype of the Kilogram (IPK), and on mass values traceable to it. This is why the experimental measurement of h needed to be high accuracy. In some sense, one may conclude that the fixed value of h has been "inherited", to use your word, from the artefact definition dating from 1889.
2. The "relative standard uncertainty" referred to in Appendix 2 is the relative standard uncertainty of h just prior to the redefinition of the kilogram. The redefinition of the kilogram was accomplished by taking the previous experimental value of h to be exact (no uncertainty). Before the redefinition, the same value of h did have an uncertainty, (unc._h) and its relative uncertainty, (unc._h)/h, must now be assigned to m(K). After 20 May 2019 when the redefinition of the kilogram will take effect, the mass m(K) must be determined experimentally.
You may notice here that your first and second question are really the same.
For a more detailed explanation, see this Short Communication:
Richard Davis
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I have a survey dataset- male and female. It has been suggested not to combine these datasets, as they were sampled differently. However, if the datasets have to be combined together, then this combined dataset can be used only if we create a combined weight for male and females. I wanted to check if someone has taken up a similar path to create a combined weight so as to use male and female datasets together.
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This question is not clear. If you are saying that the data for men were collected with a different probability of selection from the (sub)population of men, than the probability of selection for women from the (sub)population of women, then perhaps you need to study stratified random sampling. See one or two of many survey sampling textbooks, such as the classic, Sampling Techniques by William Cochran, 3rd ed, 1977, Wiley, for instance. You should also keep in mind that optimal sample allocation between strata assumes you only want inferences for overall results, but if you want good results for each stratum, then it is really like you are looking at separate subpopulations, and are doing simple random sampling from each, for example.
But perhaps the above did not address your intended question.
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There is a powder substance in 10 mg. Since it is trace amount, how to accurately weigh 1 mg to prepare the standard solution? Any special tools or tips? I am looking forward to your reply.
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After one year exploring and practice, I finally found a way to weight the trace amount of organic compounds with weight around 1 mg and here the organic means the organic solvent soluble compounds. This should also work for the water soluble compounds.
1. Make sure the sample is dry enough. Usually you purchase standards from supplier and it should be dry. In case of heavy moisture effect and vapor impact, you could dissolve in methanol or acetone and then use free drying.
2. after that, cut a plastic cap from usual 2 ml tube, weight and tare the weight of cap. You should have a precise balance such as the Mettler Toledo balance with accuracy to 0.001 mg.
3. Then, use 10 ul methanol or acetone to dissolve the dry powder, dissolve the organic compound and aliquot 10 ul to the cap. Wait until the reading is stable. (I have tried the methanol and it completely vaporized in 1 hour. Methanol lost over 95% of weight in the first 10 mins and the rest part takes a bit time to vaporize.)
4. Based on the weight, you could transfer the volume of liquid to the 2 ml tube and mix well with the solvent. You could dilute further to a designed concentration as working standards.
Notes:
1.the balance should be placed in a marble table to minimize the mechanical vibration impact from other instrument. The environment around the balance should be quite without frequent pedestrians working around. For some balance, it has small cage to lock the chamber and this design would help stabilize the reading.
2. I just try the relatively volatile organic solvent. For water, I think it should work but take longer time. 
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HI All,
It is highly admired your suggestions and opinions in advanced.
I'm wondering what is the best way to identify weight and its location simultaneously.
Example: object A is a 10kg weighted while object B is 20kg weighted. Both objects are moving around known area. But need to identify where is the A and where is the B suddenly by their weight. Any Method,suggestions?
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Thanks for all the feedback 
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I want to evaluate fresh weight of the wild type and transgenic plants after 7 days. Is there any good protocol about fresh weight measurement method?
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You need to concern a few things:
1. The age of seeds. For example, plant older wild-type seeds and newer transgenic seeds. The older seeds might have slower germination time (or other reasons), so after 7-days (this is the cut-point you start to measure your plants, as you stated in your question), the sizes of plants might be different between the wild-type and transgenic plants. This variance is not caused by your transgene.
2. The environmental factors. I don't know where you are going to grow your plants-- soil or tissue culture boxes. Except genetic factors (such as your transgenic gene), environmental factors can also affect the results of your plant sizes. For example, is the fertilizer conc. watered in the soil evenly (for each plant to grow)?
3. The number of plants (density) you grow in an area. In general, the denser the plantlets grown in an area, the smaller size the plantlets will be, due to nutrient competition.
4. Your transgenic population. If non-homogeneous, you population can contain both homozygous plants (+/+) and heterozygous plants (+/-). Some reports have shown that higher level of transgene products are observed in homozygous lines. So, when you do analysis report, you need to be aware of this. The results from homozygous and from heterozygous transgenic line can be different.
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I work with radioactively contaminated biomass. The problem is the quantity of biomass needed for experiments. Now I begin with some experiment: the biomass is in 0,5 l bottle and it seems that degradation runs. Which paramaters should I observe? I weight it, measure the temperature, pH of leachate,... what else? My possibilities are a bit limited, we never before dealt with this issue. My attention is focused on radionuclides behavior during composting process.
thanks for advice
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 size of compost systems are discussed on page 12. Various important factors are also described
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I need to supply power to a vibrating component fixed on an accurate electronic scale, but the electric wire applies a random pressure on the scale. I need to figure out how to remove or maintain a constant pressure from the wire.
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I don't undertand your answer , what do you do specific . 
I think you can try add a variables Trimmer , one lead of  trimmer connect to ground .