Question

a mother tracks the duration of her babys three daily naps for a few weeks. the mean time, in minutes, and the standard deviation, sd, for each nap are recorded in the table below.

1st nap	2nd nap	3rd nap

use the information in the table to select the true statement.
a. the 3rd nap is the least consistent in duration because its mean is the lowest.
b. the 2nd nap is the least consistent in duration because its standard deviation is the lowest.
c. the 1st nap is the least consistent in duration because its mean is the highest.
d. the 3rd nap is the least consistent in duration because its standard deviation is the highest.

Explanation:

Step1: Recall SD meaning

Standard deviation (SD) measures data consistency. Lower SD = more consistent; higher SD = less consistent. Mean relates to central tendency, not consistency.

Step2: Analyze each option

• Option A: Mean (central tendency) ≠ consistency. 3rd nap's mean low doesn't mean inconsistent. Eliminate.
• Option B: Lower SD means more consistent. 2nd nap has lowest SD (most consistent), so "least consistent" is wrong. Eliminate.
• Option C: Mean (central tendency) ≠ consistency. 1st nap's mean high doesn't mean inconsistent. Eliminate.
• Option D: 3rd nap has highest SD (11). Higher SD = less consistent. Correct.

Answer:

D. The \( 3^{\text{rd}} \) nap is the least consistent in duration because its standard deviation is the highest.