Define a z-score, and explain how it is calculated in the following example: Abby had a score of 75 on a test with a mean of 70 and a standard deviation of 5 . What is her z-score?

What will be an ideal response?

Answer will include that a z-score is a number (a standard score) that tells how many standard deviations above or below the mean score is. To convert an original score to a z-score, we subtract the mean from the score. The resulting number is then divided by the standard deviation for the group of scores. To illustrate, Abby had a score of 75 on the test with a mean of 70 and a standard deviation of 5 . Therefore, 75 minus 70 equals 5, which is divided by the standard deviation of 5 and equals 1 . So, Abby's z-score is +1.0, which means her test score of 75 is one standard deviation above the mean.

Psychology

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After collecting data, a researcher determines that states that have instituted a death penalty have shown a decrease in murders. Assuming that the data are accurate, what can you safely conclude?

a. The relationship has been brought about by another variable. b. States that do not have a death penalty should institute one as a deterrent to violent crime. c. There are fewer murders in states that have a death penalty. d. It is likely that violent criminals have moved to states that do not yet have a death penalty.

Psychology

Even though the amount of improvement declines with age, older adults can improve their memories with training and practice

Indicate whether the statement is true or false.

Psychology