A researcher wants to estimate the proportion of a population which possesses a given characteristic. A random sample of size 200 is taken and 30% of the sample possesses the characteristic. The 90% confidence interval to estimate the population proportion is _______.
p̂ = X / n = 60/200 = 0.3
p̂ ± Z(α/2) √( (p * q) / n)
0.3 ± Z(0.1/2) √( (0.3 * 0.7) / 200)
Z(α/2) = Z(0.1/2) = 1.645
Lower Limit = 0.3 - Z(0.1) √( (0.3 * 0.7) / 200) = 0.2467
upper Limit = 0.3 + Z(0.1) √( (0.3 * 0.7) / 200) = 0.3533
90% Confidence interval is ( 0.2467 , 0.3533
)
( 0.2467 < P < 0.3533 )
A researcher wants to estimate the proportion of a population which possesses a given characteristic. A...
A researcher wants to estimate the proportion of the population which possesses a given characteristic. A random sample of size 1800 is taken resulting in 450 items which possess the characteristic. The point estimate for this population proportion is _______.
A researcher wants to create a 90% confidence interval for the population proportion, with the margin of error of 3%. She has no idea what the population proportion is and she cannot take a trial sample. Calculate the required sample size.
A market researcher wants to conduct a survey to estimate the population proportion who prefer Coca-Cola to Pepsi. Before conducting the survey, the researcher wants to choose a sample size so that the half width of the 99% confidence interval is no more than 2%, regardless what he will find. What is the required sample size? Hints: recall that we only deal with "large n" population proportion questions in the class, so use the Z distribution. Also recall that the...
A market researcher wants to conduct a survey to estimate the population proportion who prefer Coca-Cola to Pepsi. Before conducting the survey, the researcher wants to choose a sample size so that the half width of the 99% confidence interval is no more than 2%, regardless what he will find. What is the required sample size? Hints: recall that we only deal with "large n" population proportion questions in the class, so use the Z distribution. Also recall that the...
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UTVU 4. If a researcher wants to estimate a population proportion to be within 4 percentage points with a 95% confidence if she uses the estimate from a recent study that showed its value to be 85%, what size sample should she obtain?
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Construct a 90% confidence interval to estimate the population proportion with a sample proportion equal to 0.44 and a sample size equal to 100. A 90% confidence interval estimates that the population proportion is between a lower limit of blank and an upper limit of. (Round to three decimal places as needed.)
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