Test Bank for Hypothesis Testing- Questions with Verified Solutions Latest Version

Test Bank for Hypothesis Testing- Questions with Verified Solutions Latest Version Hypothesis Testing - Answers We evaluate hypotheses by using sample statistics about population parameters and all statistical tests assume "random sampling." For tests of hypotheses about means - Answers We need: • A variable measured at an interval-ratio level • A variable that is normally distributed, or • A sample size larger than 50 to apply the central limit theorem The Process of Hypothesis Testing - Answers • Ask a research question • Formulate a hypothesis = tentative answer based on theory or informed reasoning ("Tentative" because the hypothesis can only be verified after empirical testing) we formulate two hypotheses - Answers • Research hypothesis (H1) • Null hypothesis (H0) Research hypothesis (H1) - Answers A substantive hypothesis expressed in terms of population parameters. • We use our sample statistics to make statements about population parameters. • H1 states that there is a difference between the two groups. (American workers differ in the number of hours they work compared to the general population (workers in industrialized nations). Null hypothesis (H0) - Answers Contradicts the research hypothesis and usually states that there is no difference between the population mean and some specified value. H0 : μy = some value (In our example: There is no difference between the number of hours worked per week by American workers compared to the general population.) Forms of a Research Hypothesis - Answers • H1 usually specifies that the population parameter is: • Not equal to some specified value: μY ≠ some value • Greater than some specified value: μY > some value • Less than some specified value: μY < some value Directional versus Non-Directional Research Hypotheses - Answers Two-Tailed Tests One-Tailed Tests Two-Tailed Tests - Answers When the researcher is interested in testing if the population mean is different from a specified value. H1 does not designate direction. • We have no theoretical basis to specify a direction, but we do believe there is some difference between the population mean and a specified value. • H1 : μy ≠ some value • H0 (The null hypothesis) is no difference. • H0 : μy = some value One-Tailed Tests - Answers H1 is directional, specifying that the population mean is greater than or less than some specified value. • If we state that the population mean is greater than some specified value, it is a right-tailed test. => H1 : μy > some value • If we state that the population mean is less than some specified value, it is a left-tailed test. => H1 : μy < some value Non-directional hypotheses (two-tailed) - Answers • Null hypothesis • American workers work the same number of hours per week than workers in industrialized countries. => H0 : μy = 40 hrs • Research hypothesis • American workers do not work the same number of hours per week than workers in industrialized countries. => H : μ ≠ 40 hrs Directional hypotheses (one-tailed) - Answers • Null hypothesis • American workers work the same number of hours per week than workers in industrialized countries. => H0 : μy = 40 hrs • Research hypotheses • American workers work more hours per week than workers in industrialized countries (right-tailed test) => H : μ > 40 hrs • American workers work less hours per week than workers in industrialized countries (left-tailed test) => H1 : μy < 40 hrs **When in doubt, use a non-directional hypothesis. ** Testing the Null Hypothesis - Answers Rather than testing H1 directly we test the null hypothesis H0 (there is no real difference in the number of hours worked) because we hope to reject the null hypothesis in order to provide support for the research hypothesis.This is why H1 is also referred to as the "alternative hypothesis".