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How should I construct a confidence interval for the population proportion p with n equals 144 and x equals 82 with a 90 percent confidence level?
Wiki User
∙ 14y ago
The confidence interval will be Pi+-z*sp
z5%= 1.6449
Pi = x/n
Sp = Sqrt(Pi(1-Pi)/n)
Pi ~= 0.5694
Sp = Sqrt(.5694*0.4306/144) ~= 0.0413
Pi - 0.0679 < p < Pi + 0.0679
0.5016 < p < 0.6373
You can do this on your TI-83/84 with 1-PropZInt (Stat->Tests->A)
Wiki User
∙ 14y ago
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What does a confidence interval for a population mean constructed from sample data show?
A confidence interval of x% is an interval such that there is an x% probability that the true population mean lies within the interval.
What is the most controllable method of increasing the precision of or narrowing the confidence interval?
Confidence intervals represent an interval that is likely, at some confidence level, to contain the true population parameter of interest. Confidence interval is always qualified by a particular confidence level, expressed as a percentage. The end points of the confidence interval can also be referred to as confidence limits.
What is Confidence Intervals of Degree of Confidence?
, the desired probabilistic level at which the obtained interval will contain the population parameter.
Does the confidence interval always contain the true population parameter?
No, the confidence interval (CI) doesn't always contain the true population parameter. A 95% CI means that there is a 95% probability that the population parameter falls within the specified CI.
What happens to the confidence interval if you increase the confidence level?
The confidence interval becomes wider.
What does a 95 percent confidence interval tell you about the population proportion?
There is a 95% probability that the true population proportion lies within the confidence interval.
What percentage of time will the population proportion not be found within the confidence interval?
What percentage of times will the mean (population proportion) not be found within the confidence interval?
When population distribution is right skewed is the interval still valid?
You probably mean the confidence interval. When you construct a confidence interval it has a percentage coverage that is based on assumptions about the population distribution. If the population distribution is skewed there is reason to believe that (a) the statistics upon which the interval are based (namely the mean and standard deviation) might well be biased, and (b) the confidence interval will not accurately cover the population value as accurately or symmetrically as expected.
What does a confidence interval for a population mean constructed from sample data show?
A confidence interval of x% is an interval such that there is an x% probability that the true population mean lies within the interval.
What is 150 out of 350 listeners to a radio program objected to the airtime of the program.construct a 99% confidence interval for the true population proportion of listeners who objected to the airtime?
Wisdom
Uwant totestcreatedWeb site so you have 250 people access it. Of the peps accessing the site 75 of them exp. computer crashes. Construct a 95 percent confidence interval for the proportion of crashes?
Estimated p = 75 / 250 = 0.3 Variance of proportion = p*(1-p)/n = 0.3(0.7)/250 =0.00084 S.D. of p is sqrt[0.00084] = 0.029 Confidence interval: phat-zval*sd = 0.3 - (1.96)(0.028983) phat-zval*sd = 0.3 + (1.96)(0.028983) Confidence interval is ( 0.2432 , 0.3568 )
How do you calculate confidence interval?
Confidence intervals may be calculated for any statistics, but the most common statistics for which CI's are computed are mean, proportion and standard deviation. I have include a link, which contains a worked out example for the confidence interval of a mean.
Which statistics are used to construct a confidence interval?
The parameters of the underlying distribution, plus the standard error of observation.
What is the most controllable method of increasing the precision of or narrowing the confidence interval?
Confidence intervals represent an interval that is likely, at some confidence level, to contain the true population parameter of interest. Confidence interval is always qualified by a particular confidence level, expressed as a percentage. The end points of the confidence interval can also be referred to as confidence limits.
Construct an 80 percent confidence interval for the true population mean given that the standard deviation of the population is 6 and the sample mean is 18?
THe answer will depend on whether the confidence interval is central or one-sided. If central, then -1.28 < z < 1.28 -1.28 < (m - 18)/6 < 1.28 -7.68 < m - 18 < 7.68 10.3 < m < 25.7
The proportion of the variation in the dependent variable y that is explained by the estimated regression equation is measured by the?
confidence interval estimate
Does the population mean have to fall within the confidence interval?
No. For instance, when you calculate a 95% confidence interval for a parameter this should be taken to mean that, if you were to repeat the entire procedure of sampling from the population and calculating the confidence interval many times then the collection of confidence intervals would include the given parameter 95% of the time. And sometimes the confidence intervals would not include the given parameter.
