its better because we often don't have to survey a large population, so a sample is quicker, easier, requires few ressources, little time and can be more accurate if a person is not there to answer it because a sample could represent that person.
Sure it can. But in the survey business, the trick is to select your sample carefully so that they'll be equal, i.e. a sample that is accurately representative of the population.
Sample is subset of the population so sample size and population size is different.However, as a subset can be the whole set, if the sample size equals the population size, you have sampled the entire population and you will be 100% accurate with your results; it may cost much more than surveying a [representative] sample, but you get the satisfaction of knowing for what you surveyed the population exactly.Using a sample is a trade off between the cost of surveying the whole population and accuracy of the result.A census is a survey of the whole population and could be considered that the sample size = population size; in this case the results are 100% accurate.The television viewing figures are calculated using a sample of the whole population and then extrapolating them to the whole population; depending upon how the same was chosen, including its size, will affect the accuracy of the results - most likely not more than 95% accurate.With a carefully selected (that is properly biased) sample you can prove almost anything!
You can estimate a population's size when counting individuals if the density in a sample is greater than the population density.
A random sample is better than a census because it takes less time and costs less.
becuase it is more accurate.
its better because we often don't have to survey a large population, so a sample is quicker, easier, requires few ressources, little time and can be more accurate if a person is not there to answer it because a sample could represent that person.
Sure it can. But in the survey business, the trick is to select your sample carefully so that they'll be equal, i.e. a sample that is accurately representative of the population.
A larger random sample will always give a better estimate of a population parameter than a smaller random sample.
It would be something like a census, surveying every last person in a given population rather than taking a random sample.
It is because the sample size for the second survey was larger.
Survey sampling involves selecting a representative subset of the population, which can be more practical and cost-effective than surveying the entire population in a census. Proper sampling techniques can still provide accurate and reliable results, as long as the sample is chosen correctly and is representative of the population of interest.
Merits: Sample surveys are cost-effective, time-efficient, and allow for data collection from a large population subset. They can provide valuable insights into attitudes, opinions, and behaviors. Demerits: Sample surveys may suffer from sampling bias, leading to results that are not representative of the population. There can also be issues with survey design, response rates, and interpretation of results.
Sample is subset of the population so sample size and population size is different.However, as a subset can be the whole set, if the sample size equals the population size, you have sampled the entire population and you will be 100% accurate with your results; it may cost much more than surveying a [representative] sample, but you get the satisfaction of knowing for what you surveyed the population exactly.Using a sample is a trade off between the cost of surveying the whole population and accuracy of the result.A census is a survey of the whole population and could be considered that the sample size = population size; in this case the results are 100% accurate.The television viewing figures are calculated using a sample of the whole population and then extrapolating them to the whole population; depending upon how the same was chosen, including its size, will affect the accuracy of the results - most likely not more than 95% accurate.With a carefully selected (that is properly biased) sample you can prove almost anything!
No, it is not true. All that a sample gives you is an estimate about what the distribution might look like in the entire population. If you know what the distribution in the population looks like you have an error free fact and no estimate can better than that. another way to look at that: the bigger a sample gets the better the accuracy of the estimate. The sample cannot be bigger than the population however. The one caveat is in the data collection process. Under certain circumstances a sample may be more precise when data collection is difficult or flawed.
A sample survey may be preferable than a census because it can be more comprehensive. While its research only involves a subset, it is typically more accurate.
When you don't have the population standard deviation, but do have the sample standard deviation. The Z score will be better to do as long as it is possible to do it.