sample mean

sample mean : In mathematics and statistics, the arithmetic mean (or simply the mean) of a list of numbers is the sum of all of the list divided by the number of items in the list. If the list is a statistical population, then the mean of that population is called a population mean. If the list is a statistical sample, we call the resulting statistic a sample mean. The mean is the most commonly-used type of average and is often referred to simply as the average. The term "mean" or "arithmetic mean" is preferred in mathematics and statistics to distinguish it from other averages such as the median and the mode. If we denote a set of data by X = ( x 1, x 2, ..., x n), then the sample mean is typically denoted with a horizontal bar over the variable ($\backslash bar\{x\}\; \backslash ,$, enunciated " x bar"). The Greek letter μ is used to denote the arithmetic mean of an entire population. Or, for a random variable that has a defined mean, μ is the probabilistic mean or expected..   More from Wikipedia

sample mean : ms:Templat:MathTopicTOC S-duality -- S-matrix -- S plane -- S transform -- S-unit -- S.O.S. Mathematics -- SA subgroup -- Saccheri–Legendre theorem -- Saccheri quadrilateral -- Sacks spiral -- Sacred geometry -- Saddle-node bifurcation -- Saddle point..   More from Wikipedia

 

  The difference between the mean of a sample and the mean of a population.

Question : About to have my final and still can't figure this study problem out any help would be appreciated A TV Station estimates 55% of college students watch the Super Bowl. For a sample of 280 students selected at random, what is the mean and variance if those who watched the game?

Answer : Trick Question!!!! This is Proportion Question: 55% is your answer. (there is no "mean") Probability of watching Superbowl is 280 * 0.55 = 154 students likely to have watched Superbowl from Sample...   More from Yahoo Answers

Question : A sample of 81 observations is taken from a normal population. The sample mean is 40, and the sample standard deviation is 5. Determine the 95 percent confident interval for the population mean.

Answer : The formula for a confidence interval: xbar z * (s / sqrt(n)) Where: xbar = sample mean s = sample standard deviation n = number of observations z = 1.96 (from table lookup) Since n >30, we assume a normal distribution and the sample standard deviation can be substituted for the population standard deviation. The confidence interval is : = xbar z * (s / sqrt(n)) = 40 1.96 * (5 / sqrt(81)) = 40 1.96 * (5 / 9) = 40 1.089 = 38.911 to 41.089 Good luck in your studies, ~ Mitch ~..   More from Yahoo Answers

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