Generating Research Questions for z-Tests and t-Tests

Standard score—Also known as a z-score. A standard score gives us the position of a data value comparison to the mean. We also knew, by looking at the z score, whether this was a great score or not. Remember that a z score tells you, in standard deviation units, how far away the score is from the mean. Positive scores are above the mean while negative scores are below the mean. A z-score of 2.12 on a national exam is great. We have scored 2.12 standard deviations ABOVE the mean!! How rare is that? If we looked at our graph of a normal distribution below, we can see that going out just two standard deviations from the mean on each side covers at least 95% of the distribution. Our score puts us past that, into the less than 5% area in the tails of the distribution (and since we are looking only toward one tail that indicates even a smaller percent of people who did as well as we did).

Types of T-Test

1. One-Sample

2. Dependent (Repeated_ Samples

3. Independent Samples

By Saturday, June 7, 2014 , post your response to the prompt in the Discussion Area below. Present the rationale for your selection. Be very specific in your presentation. Through Wednesday, June 11, 2014 , review and comment on at least two peers’ responses, wherein you present your feedback regarding the research questions proposed.