## PSYC 354 Quiz 4

**PSYC 354 Quiz 4: Standard Deviation and z-Scores **

- Which
*z*-score corresponds to a score that is above the mean by 2 standard deviations? - One purpose of a z-score is to provide an understanding of the exact location of a score in a distribution.
- Which z-score value represents the location farthest from the mean?
- Transforming an entire distribution of scores into z-scores changes an originally positively skewed distribution to a negatively skewed z-score distribution.
- Transforming a set of scores into a standardized distribution of z-scores consists of graphically _____ the scores.
- For any distribution, what is the
*z*-score corresponding to the mean? - A positive
*z*-score always corresponds to a score that is greater than the mean in a distribution. - Which position in a distribution corresponds to a
*z*-score of*z*= –1.00? - Consider a population that has a score of
*X*= 15 associated with a*z*-score of +1.50. What does this z-score indicate about the location of*X*= 15? - For a population with
*μ*= 40 and*σ*= 8, what is the*z*-score corresponding to*X*= 34? - A score that is 6 points above the mean corresponds to a z-score of
*z*= +0.50. For this population, the standard deviation is*σ*= 12. - For a population with a mean of
*μ*= 60 and a standard deviation of*σ*= 4, a score of*X*= 56 corresponds to a z-score of*z*= –0.50.

- For a sample with
*s*= 9, a score of*X*= 67 corresponds to*z*= +1.00. What is the sample mean? - For a sample with
*M*= 50 and*s*= 12, what is the*X*value corresponding to*z*= –0.25? - A population has
*μ*= 50. Which value of*σ*would make*X*= 55 an extreme value out in the tail of the population distribution?