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Tag Archives: Confidence Interval

Inferences for Population Proportions


Confidence Intervals for One Population Proportion Statisticicans often need to determine the proportion (percentage) of a population that has a specific attribute. Some examples are: the percentage of U.S. adults who have health insurance the percentage of cars in the United States that are imports the percentage of U.S. adults who favor stricter clean air […]

Statistic Procedures – Confidence Interval


Confidence Intervals for One Population Mean A common problem in statistics is to obtain information about the mean, μ, of a population. One way to obtain information about a population mean μ without taking a census is to estimate it by a sample mean x(bar). So, a point estimate of a parameter is the value of a […]

How to compute the expected 95% CI


The Random Sampling Distribution of Means Imagine you have a hat containing 100 cards, numbered from 0 to 99. At random, you take out five cards, record the number written on each one, and find the mean of these five numbers. Then you put the cards back in the hat and draw another random sample, […]

Evaluate The Article About Therapy (Randomized Trials)


Section 1 How Serious Is The Risk of Bias? Did Intervention and Control Groups Start With The Same Prognosis? Consider the question of whether hospital care prolongs life. A study finds that more sick people die in the hospital than in the community. We would easily reject the naive conclusion that hospital care kills people […]