Submit completed tests as word or pdf files via email to paul.kurose@seattlecolleges.edu
Due: Sunday, May 19 (by 8am).
1. a) In Chapter 6, you learned to find interval estimates for two population parameters, a population mean and a population proportion. Explain the meaning of an interval estimate of a population parameter.
An interval estimate for a specified population parameter (such as a mean or proportion) is a range of values in which the parameter is estimated to lie. In Chapter 6, you were assigned to find interval estimates for a population mean and a population proportion. b) Is finding an interval estimate an example of inferential or descriptive statistics? Explain.
It is an interval estimate is an example of
…show more content…
Explain your reasoning. The confidence level will increase the margin of error of a Confidence-interval estimate.
d) If confidence level is kept constant, what effect will an increase in sample size have on the margin of error of a confidence interval estimate? Explain your reasoning. An increase in sample size will decrease the margin of error of a
Confidence-interval estimate.
3. a) A simple random sample of thirty-six students has a mean age equal to 25 years. Given =4.8 years, determine a 90% confidence interval estimate for µ. E ≤0.8, µ = 25 so The 90% confidence interval is 25 ± 1.32 = 23.68 and 26.32
b) Determine the sample size required to have a (smaller) margin of error of 0.8 years for a (higher) 95% confidence level for the confidence interval estimate for µ in part a) above. The sample size should be n ≥ 138.3 ≈ 139 for a 95% confidence level
4. A) In a simple random sample of students from colleges across the state of Washington, 490 are in favor decreasing the size of their college administration and 310 are not. Determine a 95% confidence interval estimate for the proportion of Washington college students who favor decreasing the size of their college administration. With a 95% confidence, I can say the proportion of Washington college students who favor decreasing the size of their college administration
(21) You took a sample of size 21 from a normal distribution with a known standard deviation, . In order to find a 90% confidence interval for the mean, You need to find.
Determine the minimum sample size required to construct a 95% confidence interval for the population mean. Assume the population's standard deviation is .2 inches.
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
If the CEO wants to have 95.44 percent confidence that the estimates of awareness and positive image are within +/- 2 percent of true value, the required sample size should be 2221. I came up with that answer by doing the following:
Results from previous studies showed 79% of all high school seniors from a certain city plan to attend college after graduation. A random sample of 200 high school seniors from this city reveals that 162 plan to attend college. Does this indicate that the percentage has increased from that of previous studies? Test at the 5% level of significance.
a) Does the range rule of thumb overestimate or underestimate the standard deviation for the number of people living in your home? Q17
A skeptical paranormal researcher claims that the proportion of Americans that have seen a UFO is less than 1 in every one thousand. State the null hypothesis and the alternative hypothesis for a test of significance.
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).
In this case a sample size of 100 would be better. This can be explained using law of averages and also by looking at the formula for Margin of Error.
9. Assume you want to estimate with the proportion of students who commute less than 5 miles to work within 2%, what sample size would you need?
The confidence interval is used as a type of interval estimate of a sample population to indicate the reliability of the
The customers in this case study have complained that the bottling company provides less than the advertised sixteen ounces of product. They need to determine if there is enough evidence to conclude the soda bottles do not contain sixteen ounces. The sample size of sodas is 30 and has a mean of 14.9. The standard deviation is found to be 0.55. With these calculations and a confidence level of 95%, the confidence interval would be 0.2. There is a 95% certainty that the true population mean falls within the range of 14.7 to 15.1.
A field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the .10 level of significance, that
Develop 95% confidence intervals for the proportion of subscribers who have broadband access at home and proportion of subscribers who have children.
3) The confidence interval is one of the parameters that estimates or demonstrates the relationship between the results found in the sample and a characteristic in the population. There is a 95% probability that the education level of the population is between -1.95 and -1.07. Since the null value(0) is not part of the interval, there is statistical significance. The results for gender fall between 0.07 and -5.21, since the confidence interval includes 0, it is not statically significant. The results for immigration fall between 4.08 and -1.6, since the result also includes 0 in the interval, there is no statistical significance. The confidence interval results for religion fall between 12.76 and 6.44, proving there is statistical significance between the