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.