The Test Statistic Hypothesis testing involves the use of distributions of known area, like the normal distribution, to estimate the probability of obtaining a certain value as a result of chance. The researcher is usually testing to see if the probability will be low because that means it is likely that the test result was not a mere coincidence but occurred because the researcher's theory is correct. It could mean, for example, that it is probably not just bad luck but faulty packaging equipment that caused you to get a box of raisin cereal with only five raisins in it. Only two outcomes of a hypothesis test are possible: Either the null hypothesis is rejected, or it is not. You have seen that values from normally distributed populations can be converted to z-scores and their probabilities looked up in Table 2 in "Statistics Tables." The
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