Answer:
a)
Z = -1.58 means that a reading speed of 340 wpm is 1.58 standard deviations below the mean reading speed.
b)
Z = 0.67 means that a reading speed of 475 wpm is 0.67 standard deviations above the mean reading speed.
c)
Z = -0.25 means that a reading speed of 420 wpm is 0.25 standard deviations below the mean reading speed.
d)
Z = 2.92 means that a reading speed of 610 wpm is 2.92 standard deviations above the mean reading speed.
Step-by-step explanation:
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The z-score measures how many standard deviations a measure X is above or below the mean.
In this problem, we have that:
a. 340 wpm
Z = -1.58 means that a reading speed of 340 wpm is 1.58 standard deviations below the mean reading speed.
b. 475 wpm
Z = 0.67 means that a reading speed of 475 wpm is 0.67 standard deviations above the mean reading speed.
c. 420wpm
Z = -0.25 means that a reading speed of 420 wpm is 0.25 standard deviations below the mean reading speed.
d. 610wpm
Z = 2.92 means that a reading speed of 610 wpm is 2.92 standard deviations above the mean reading speed.