TRIGONOMETRY from the above word write down the letters which have exactly two lines of symmetry and rotational symmetry of order 2

Sampling errorthe natural discrepancy, or amount of error, between a sample statistic and its corresponding population parameterthe distribution of sample meansthe collection of sample means for all the possible random samples of a particular size (n) that can be obtained from a populationa sampling distributiona distribution of statistics obtained by electing all the possible samples of specifics size from a of the distribution of sample means1. should pile up around population mean/be representative of the population2. should form a normal-shaped distribution  3. the larger the sample size, the closer the sample means should be to the population meancentral limit theorem-provides a precise description of the distribution that would be obtained if you selected every possible sample, calculated every sample mean, and constructed the distribution of the sample meanthe shape of the distribution of sample meansthe distribution is almost perfectly normal if either of these conditions are satisfied: 1. the population from which the samples are selected is a normal distr.2. the number of scores (n) in each sample is rel. large, around 30/+the expected value of m-the mean of the distribution of sample means-is always identical to the population meanthe standard error of m-the standard deviation of the distribution of sample means  -provides a measure of how much distance is expected on average between a sample mean (m) and the population mean (u)purposes of the standard error of m1. describes the distribution of the sample means; provides measure of how much difference is expected from sample to sample  2. measures how well an individual sample mean represents the entire distribution; provides measure of how much distance is reasonable to expect between a sample mean and the overall mean for the distr.  -also provides a measure of how much distance to expect between a sample mean (m) and population mean, muthe magnitude of the standard error is determined . the size of the sample2. the standard deviation of the population from which the sample is selectedthe law of numbersthe larger the sample size (n), the more probable it is that the sample mean will be close to the population meanwhat is the primary use of the distribution of sample means? to find the probability associated with any specific sample  -probability is equivalent to proportion