Introduction to Hypothesis Testing

Hypothesis Testing The general goal of a hypothesis test is to rule out chance (sampling error) as a plausible explanation for the results from a research study. Hypothesis testing is a technique to help determine whether a specific treatment has an effect on the individuals in a population.

Hypothesis Testing Steps The following five steps outline the process of hypothesis testing and introduce some of the new terminology:

Hypothesis Testing Steps Step 1: State the hypotheses.  null hypothesis (H 0 ) VS alternate (H 1 ) ] Step 2: State the criteria for a decision  =.05 (5%)  =.01 (1%)  =.001 (0.1%) Step 3: Compute the test statistic.

Hypothesis Testing Steps Step 4: Making a statistical decision  Reject null hypothesis VS fail to reject Step 5: Stating a conclusion – stating what the results mean.

Example Researcher is interested in developmental theory and would like to determine whether or not stimulation during infancy has an effect on human development. Mean weight for 2-year-old children is μ = 26 pounds. The distribution of weights is normal with σ = 4 pounds. Researcher obtains a sample of n = 16 newborn infants and give their parents detailed instructions for giving their children increased handling and stimulation.

Example 2 Suppose that scores on the SAT form a normal distribution with  =500 and  =100. A high school counselor has developed a special course to boost SAT scores. A random sample of n=16 students is selected to take the course and then the SAT. The sample had an average score of M=554. Does the course have an effect on SAT scores?

Example 2 Comparison Population Normal  =500  =100 Sample N=16 M=554