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Example of panel sampling?
A good example to panel sampling will be sampling the performance of a group of companies in a specified region. This way they the samples can be revisited at a later stage thus panel sampling.
Use the guess-and-check method to solve the equation?
OK for very simple equations but not much good otherwise.
What is answer of 366025 if want to find square root by division method?
The square root of 366,025 is 605. I don't know the division method, but that doesn't matter. The result is the same no matter what method you use to find it. If you work the same problem by two different methods and get two different answers, then at least one of them is wrong, and there's a good chance that they both are.
Mr Johnson made 4 gallons of chili He will put the chilli into 1 quart containers How many 1 quarts containers will he fill?
4 gallons of not-so-good chili would fill 16 1-quart containers. However, if the chili is any good, there won't be 16 quarts left -- the "sampling" will considerably diminish the quantity available to put into containers.
Why is it important to have two sets of temperature data?
If both sets are in agreement, it is a good indication each is accurate. If, on the other hand, there is great disparity between the two sets, we may conclude there is some significant error in our data gathering or sampling technique. The NASA GISS data (see link) include both a land/sea temperature index and temperature measurements from meteorological stations.
Concept of Probability sampling and chi square test?
A probability sampling method is any method of sampling that utilizes some form of random selection. See: http://www.socialresearchmethods.net/kb/sampprob.php The simple random sample is an assumption when the chi-square distribution is used as the sampling distribution of the calculated variance (s^2). The second assumption is that the particular variable is normally distributed. It may not be in the sample, but it is assumed that the variable is normally distributed in the population. For a very good discussion of the chi-square test, see: http://en.wikipedia.org/wiki/Pearson%27s_chi-square_test
How to reduce sampling error?
The only way to get rid of sampling error is to use the entire population under study. This is usually impossible, so the next best thing is to use large samples and good sampling methods.
What is the significance of sampling in research and what are the characteristics of a good sample?
Sampling is important as data collected is used to test the hypothesis. A good sample is a true representation of the general population. In addition, it should be flexible and focus on the research objectives.
The kind of sampling strategy least likely to produce statistics that are good estimates of population parameters is a?
Haphazard sample
You are in charge of promoting a new flavor of toothpaste yet to be produced in a toothpaste manufacturing unit which sampling techniques will you use to get the required data from a population?
Sampling is that part of statistical practice concerned with the selection of individual observations intended to yield some knowledge about a population of concern, especially for the purposes of statistical inference. Each observation measures one or more properties (weight, location, etc.) of an observable entity enumerated to distinguish objects or individuals. Survey weights often need to be applied to the data to adjust for the sample design. Results from probability theory and statistical theory are employed to guide practice. In business, sampling is widely used for gathering information about a populationIt is incumbent on the researcher to clearly define the target population. There are no strict rules to follow, and the researcher must rely on logic and judgment. The population is defined in keeping with the objectives of the study.Sometimes, the entire population will be sufficiently small, and the researcher can include the entire population in the study. This type of research is called a census study because data is gathered on every member of the population.Usually, the population is too large for the researcher to attempt to survey all of its members. A small, but carefully chosen sample can be used to represent the population. The sample reflects the characteristics of the population from which it is drawn.Sampling methods are classified as either probability or non-probability. In probability samples, each member of the population has a known non-zero probability of being selected. Probability methods include random sampling, systematic sampling, and stratified sampling. In non-probability sampling, members are selected from the population in some non-random manner. These include convenience sampling, judgment sampling, quota sampling, and snowball sampling. The advantage of probability sampling is that sampling error can be calculated. Sampling error is the degree to which a sample might differ from the population. When inferring to the population, results are reported plus or minus the sampling error. In non probability sampling, the degree to which the sample differs from the population remains unknown.· Random samplingis the purest form of probability sampling. Each member of the population has an equal and known chance of being selected. When there are very large populations, it is often difficult or impossible to identify every member of the population, so the pool of available subjects becomes biased.· Systematic sampling is often used instead of random sampling. It is also called an Nth name selection technique. After the required sample size has been calculated, every Nth record is selected from a list of population members. As long as the list does not contain any hidden order, this sampling method is as good as the random sampling method. Its only advantage over the random sampling technique is simplicity. Systematic sampling is frequently used to select a specified number of records from a computer file.· Stratified sampling is commonly used probability method that is superior to random sampling because it reduces sampling error. A stratum is a subset of the population that share at least one common characteristic. Examples of stratums might be males and females, or managers and non-managers. The researcher first identifies the relevant stratums and their actual representation in the population. Random sampling is then used to select a sufficient number of subjects from each stratum. "Sufficient" refers to a sample size large enough for us to be reasonably confident that the stratum represents the population. Stratified sampling is often used when one or more of the stratums in the population have a low incidence relative to the other stratums.· Convenience sampling is used in exploratory research where the researcher is interested in getting an inexpensive approximation of the truth. As the name implies, the sample is selected because they are convenient. This non-probability method is often used during preliminary research efforts to get a gross estimate of the results, without incurring the cost or time required to select a random sample.· Judgment sampling is a common non-probability method. The researcher selects the sample based on judgment. This is usually an extension of convenience sampling. For example, a researcher may decide to draw the entire sample from one "representative" city, even though the population includes all cities. When using this method, the researcher must be confident that the chosen sample is truly representative of the entire population.· Quota samplingis the non-probability equivalent of stratified sampling. Like stratified sampling, the researcher first identifies the stratums and their proportions as they are represented in the population. Then convenience or judgment sampling is used to select the required number of subjects from each stratum. This differs from stratified sampling, where the stratums are filled by random sampling.· Snowball sampling is a special non-probability method used when the desired sample characteristic is rare. It may be extremely difficult or cost prohibitive to locate respondents in these situations. Snowball sampling relies on referrals from initial subjects to generate additional subjects. While this technique can dramatically lower search costs, it comes at the expense of introducing bias because the technique itself reduces the likelihood that the sample will represent a good cross section from the population.If I were an officer to promote a new flavour of toothpaste yet to be produced, I would use RANDOM SAMPLING METHODØ Random sampling:Random sampling- all members of the population have an equal chance of being selected as part of the sample. You might think this means just standing in the street and asking passers-by to answer your questions. However, there would be many members of the population who would not be in the street at the time you are there; therefore, they do not stand any chance of being part of your sample. To pick a random sample, it is necessary to take all the names on the electoral register (A list of all the people who live in a particular area) and pick out, for example, every fiftieth name. This particular person needs to be interviewed to make the sample truly random. Random sampling is very expensive and time consuming, but gives a true sample of the population.Types of Random sample:A simple random sample is selected so that all samples of the same size have an equal chance of being selected from the population.A self-weighting sample, also known as an EPSEM (Equal Probability of Selection Method) sample, is one in which every individual, or object, in the population of interest has an equal opportunity of being selected for the sample. Simple random samples are self-weighting.Stratified sampling involves selecting independent samples from a number of subpopulations, group or strata within the population. Great gains in efficiency are sometimes possible from judicious stratification.Cluster sampling involves selecting the sample units in groups. For example, a sample of telephone calls may be collected by first taking a collection of telephone lines and collecting all the calls on the sampled lines. The analysis of cluster samples must take into account the intra-cluster correlation which reflects the fact that units in the same cluster are likely to be more similar than two units picked at randomØ Pros and Cons:1. There are lot of bias in Random sampling2. It is feasible and simple as the sampling is done on a random basis.3. Can make sample units in groups.4. Very expensive and time consuming, but gives a true result of the population5. While in toothpaste case, the users can given a sample piece of toothpaste randomly to get the feedback or their opinion from the chosen populationConclusion: Though the Random sampling has couple of de-merits it will help to figure out the result from the chosen population. While all other also may provide the result which may not be best comparing to the sampling method which I have chosen (Random Sampling)
Is Starbucks coffee a homogeneous or heterogeneous good?
heterogeneous
Which sampling method would be best for a large multi-site corporation employee survey?
When carrying out a multi-site corporation employee survey, stratified sampling will give good results. Subsets of the employees, called strata, are used to save time and resources.
When population distribution is right skewed is the sampling also with right skewed distribution?
If the population distribution is roughly normal, the sampling distribution should also show a roughly normal distribution regardless of whether it is a large or small sample size. If a population distribution shows skew (in this case skewed right), the Central Limit Theorem states that if the sample size is large enough, the sampling distribution should show little skew and should be roughly normal. However, if the sampling distribution is too small, the sampling distribution will likely also show skew and will not be normal. Although it is difficult to say for sure "how big must a sample size be to eliminate any population skew", the 15/40 rule gives a good idea of whether a sample size is big enough. If the population is skewed and you have fewer that 15 samples, you will likely also have a skewed sampling distribution. If the population is skewed and you have more that 40 samples, your sampling distribution will likely be roughly normal.
Example of panel sampling?
A good example to panel sampling will be sampling the performance of a group of companies in a specified region. This way they the samples can be revisited at a later stage thus panel sampling.
Why its is necessary to use sampling in statistical investigation?
Sampling gives good insight of the choosen sample
How could a scientist use sampling to investigate the health of the deer population in a forest preserve?
To see what medicine is good to get them healthy so their body could get more energy
How could a scientist use sampling to investigate the health of deer population in a forest preserve?
To see what medicine is good to get them healthy so their body could get more energy
