Find the z-score corresponding to the given value and use the z-score to determine whether the value is unusual.
Consider a score to be unusual if its z-score is less than -2.00 or greater than 2.00. Round the z-score to the nearest tenth
if necessary.
-A time for the 100 meter sprint of 14.9 seconds at a school where the mean time for the 100 meter sprint is 17.6 seconds and the standard deviation is 2.1 seconds.
A) -1.3; not unusual
B) -2.7; unusual
C) 1.3; not unusual
D) -1.3; unusual

Question

Quizplus · Accepted Answer

To find the z-score, we use the formula:
z = (x - μ) / σ
where x is the given value, μ is the mean, and σ is the standard deviation.

For the 100 meter sprint time of 14.9 seconds, the z-score is:
z = (14.9 - 17.6) / 2.1 = -1.3

Since the z-score of -1.3 is not less than -2.00 or greater than 2.00, we can conclude that the time of 14.9 seconds is not unusual.

Find the Z-Score Corresponding to the Given Value and Use