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Stack #65663
| Question | Answer |
|---|---|
| a parameter is | a number that describes a population |
| a statisctic is | a number that can be computed from sample data without making use of any unknown parameterss |
| two most common statistics are | x (sample mean) and p (p hat) |
| statistics are used to | estimate parameters |
| sampling variablility | sicne differnt samples yield diffren vlaues of the statistic in question, the varaition is called the sampling variable |
| sampling distribution of a statistic | is the distribution of values taken by the statistics in all possible samples of the same size from the same population |
| standard devation of a sample statistic is called | the standard error of the statistic |
| sampling distribtions are described by examining | the sahpe of its graph, the center, its starndard dev, and outliers |
| a measurment porcess is biased if | it systematically overstrates or udnerstats the true value of the variable it attemps to estimate |
| a statistic used to estimate a parameter is unbiased | if the mean of the sampling distribution is equal to the true value of the parameter being estimated |
| the sampling distribution of p hat is | approximately normal and closer to a normal distribution when the sample size n is large |
| normal distributions are used to approximate the sampling distribution of p when both | np>10 and nq > 10 |
| the mean of p hat is | p (uphat=p) |
| the satnadrd dev of p hat is | square root of pq/n |
| if a population has a normla distribution then xbar of n independent observations | is normally distributed, has a mean of mu, has a standard dev of sigma/ root n which is smasller than the population satndard dev |
| CLT | draw an srs of size n from an population with mean mu and finite standard deviation. when n is large the sampling sitruibtion of the sample mean x bar is approxiately normal with mean mu and satndard deviation sigma over root n |