9.4 Hypothesis Testing & the t-Distribution

randomization condition

the data is drawn from a random sample - one of the conditions that must be true to use the student’s t

SE(ȳ) = s/√n

the formula for the standard error of the mean

t_df = (ȳ - μ) / (s/√n)

the formula for the test statistic in hypothesis testing - in this formula, the subscript refers to degrees of freedom

one-sample t-test for the mean

a statistical test you can use to compare a sample statistic to an estimated population parameter - this test can be used to determine if there is evidence that the mean of the sample is different from the mean of the population of interest

10% condition

the sample size is less than 10% of the population - one of the conditions that must be true to use the student’s t

nearly normal condition

the data comes from a distribution that is unimodal and symmetrical, without skewness or outliers - one of the conditions that must be true to use the student’s t

degrees of freedom

the number of scores or values in a distribution that are free to vary