Question

lena wants to find the average height of students in the 9th grade at washington high school. so she will use a sample of students in the 9th grade to find the average height. answer the questions below. (a) which unit(s) could be used for the unit of measurement? check all that apply. minutes meters centimeters millimeters seconds (b) which of the procedures below would be the best way to find the average height? measure the heights of 5 volunteers from the 9th grade. ask for 20 volunteers from the 9th grade to state their own heights. randomly pick 5 students from the 9th grade and have them state their own heights. randomly pick 20 students from the 9th grade and measure their heights.

Explanation:

(a) For measuring human height, meters and centimeters are appropriate units (meters for general expression, centimeters for more precision; minutes/seconds are time units, millimeters are overly precise for height).
(b) To get a representative average, a random, adequately sized sample with measured (not self-reported, which is less accurate) heights is best. 20 randomly picked students measured directly avoids bias and has a sufficient sample size.

Answer:

(a) meters, centimeters
(b) Randomly pick 20 students from the 9th grade and measure their heights.