Suppose x has a mound-shaped distribution with σ= 3.
(a) Find the minimal sample size required so that for a 95% confidence interval, the maximal margin of error is E=0.4.
(b) Based on this sample size, can we assume that the x distribution is approximately normal? Explain.
Suppose x has a mound-shaped distribution with σ= 3. (a) Find the minimal sample size required...
What is the minimal sample size needed for a 95% confidence interval to have a maximal margin of error of 0.1 in the following scenarios? (Round your answers up the nearest whole number.) (a) a preliminary estimate for ρ is 0.14 (b) there is no preliminary estimate for p
Allen's hummingbird (Selasphorus sasin) has been studied by zoologist Bill Alther.† Suppose a small group of 11 Allen's hummingbirds has been under study in Arizona. The average weight for these birds is x = 3.15 grams. Based on previous studies, we can assume that the weights of Allen's hummingbirds have a normal distribution, with σ = 0.28 gram. (a) Find an 80% confidence interval for the average weights of Allen's hummingbirds in the study region. What is the margin of...
mpirical Rule data set which is mound-shaped or approximately mound-sha Forroximately normal), the following statements will hold: 68% of the observations will lie within μ ~95% of the observations will lie within μ -99.7% of the observations will lie within (i.e., normal or app σ 2σ . 3 . Consider a r.v., Z, with a standard normal distribution. We can co Empirical Rule using the Standard Normal Table. nfirm each of the statements in the Note,' Since Z ~ N...
What is the minimal sample size needed for a 90% confidence interval to have a maximal margin of error of 0.05 if there is no preliminary estimate for p?
What is the minimal sample size needed for a 95% confidence interval to have a maximal margin of error of 0.1 in the following scenarios? (For each answer, enter a number. Round your answers up the nearest whole number.) (a) a preliminary estimate for p is 0.38 (b) there is no preliminary estimate for p
4. Sample Size What is the minimal sample size needed for a 99% confidence interval to have a maximal margin of error of 0.06: if a preliminary estimate for p is 0.8? if there is no preliminary estimate for p? 5. Myers-Briggs: Actors Isabel Briggs Myers was a pioneer in the study of personality types. The following information is taken from MBTI Manual: A Guide to the Development and Use of the Myers-Briggs Type Indicator by Myers and McCaulley (Consulting...
Allen's hummingbird (Selasphorus sasin) has been studied by zoologist Bill Alther.† Suppose a small group of 18 Allen's hummingbirds has been under study in Arizona. The average weight for these birds is x = 3.15 grams. Based on previous studies, we can assume that the weights of Allen's hummingbirds have a normal distribution, with σ = 0.36 gram. (a) Find an 80% confidence interval for the average weights of Allen's hummingbirds in the study region. What is the margin of...
A random sample of 16 values is drawn from a mound-shaped and symmetric distribution. The sample mean is 15 and the sample standard deviation is 2. Use a level of significance of 0.05 to conduct a two-tailed test of the claim that the population mean is 14.5. (a) Is it appropriate to use a Student's t distribution? Explain. Yes, because the x distribution is mound-shaped and symmetric and σ is unknown.No, the x distribution is skewed left. No, the x distribution...
Consider a 90% confidence interval for µ not known. For which sample size, n = 10 or n = 20, is the confidence interval longer? Critical Thinking Lorraine computed a confidence interval for µ based on a sample of size 41. Since she did not know α, she used s in her calculations. Lorraine used the normal distribution for the confidence interval instead of a Student's t distribution. Was her interval longer or shorter than one obtained by using an...
7.5 Suppose you draw a random sample of size n from a normal distribution with unknown mean u and known standard deviation o and construct a 95% confidence interval for u. If you want to halve the margin of error, how much larger would the sample size have to be?