1.Why is it often impossible to know the actual value of any population parameter? Give an example of a population parameter that you cannot calculate, but that you can estimate. It’s impossible to know the actual value of any population parameter. The researchers studied only a sample portion (Bennett, 2012). A population parameter that you cannot calculate would average height of every woman in the military. Getting each female height in the military is impossible. 2. A sample can be used to estimate a population parameter. How does the sample size affect the estimate? If the sample is larger, what will this do to the error E? The sample size increases affect the estimate. As the sample size increases, the margin of error decreases.
- Because all available data was used, there is a greater sample in our analysis. We assume that more data points will lead to a more accurate conclusion.
6. Based on questions 3, 4, and 5 is the mean or median a better estimate for the parameter of interest? Explain your reasoning.
6. Based on questions 3, 4, and 5 is the mean or median a better estimate for the parameter of interest? Explain your reasoning.
12. _____ For a given population, confidence intervals constructed from larger samples tend to be narrower than those constructed from smaller samples. Which statement below best describes why this is true? (A) The variability of the sample mean is less for larger samples. (B) The z-value for larger samples tends to be more accurate. (C) The population variance is larger for large populations. (D) As the sample size increases, the z-value (or t-value) becomes smaller. A machine dispenses potato chips into bags that are advertised as containing one pound of product. To be on the safe side, the machine is supposed to be calibrated to dispense 16.07 ounces per bag, and from long time observation, the distribution of the fill-weights is known to be approximately normal and the process is known to have a standard deviation of 0.15 ounces.
If the population of disease plants was clustered, then the sample size will increase because it will increase standard deviation and variance of the population which increases the size of the population.
Population A and Population B both have a mean height of 70.0 inches with an SD of 6.0. A random sample of 30 people is picked from population A, and random sample of 50 people is selected from Population B. Which sample mean will probably yield a more accurate estimate of its population mean? Why? Despite, both Population A and Population having a mean height of 70.0 inches with an SD of 6.0, Population B will
Compare predictions for human population growth in developed countries versus developing countries. Why is it difficult to predict the growth of Earth’s human population? Why should population growth be predicted?”? What will happen if there is exponential human growth?
21. What is sampling error? Could the value of the sampling error be zero? If it were zero, what would this mean?
1. A researcher is interested in whether students who attend private high schools have higher average SAT Scores than students in the general population. A random sample of 90 students at a private high school is tested and and a mean SAT score of 1030 is obtained. The average score for public high school student is 1000 (σ= 200).
10. When using the Chebyshev 's theorem to obtain the bounds for a 99.73 percent of the values in a population, the interval generally will be ___________ the interval obtained for the same percentage
Be sure to show the data from your sample and the data to support your estimate.
a 1988 DOD Survey of men and women in the military and found that 51.8 % of men
the US civilian population, which was about 33% in men and 27% of women aged 20-39
Choice (a) is wrong. The estimate from Johns Hopkins cannot have less sampling variability since it has a smaller sample size (60) compared to Ohio State (1,200); only larger samples give a smaller spread. Choice (c) is untrue since the sample size of Johns Hopkins (60) is not the same size as Ohio State (1,200), so it is not possible for both schools to have the same sampling variability. Choice (d) would be wrong since it is possible to make a statement about the sampling variability of the two estimates, by using the given number of undergraduates and the provided sample sizes which made choice (b) true. Choice (e) would be untrue since as mentioned above, (b) is the correct answer due to the fact that smaller samples give a larger spread and larger samples give a smaller spread, and so the option for none of the answers to be the best
The margin of error decreases as the sample size increases. The higher the margin of error, the less likely it is that the results are true for the whole population. Even though my data is not all normally distributed, the margin of error can still be a useful