Answer:
B. 95% confident the average concentration of PCBs in the water supply is between 2.9 ppb and 3.5 ppb
Step-by-step explanation:
You are given the total number of samples, the concentration of lead, and the standard deviation. The standard deviation represents how inaccurate the estimation of the concentration of lead in the drinking water. This means that there can only possibly be a 0.3 ppb error in the estimation. 3.2-0.3=2.9, and 3.2+0.3=3.5
Answer:146
Step-by-step explanation:
B) 12 inches would be the most accurate measurement.
Since the ruler is exactly 1 foot long, the most accurate measurement is 12 inches. 12.005 is a tempting answer, since it is the most specific/exact, but 12 inches is the most accurate, since this is equal to exactly one foot.
<span>Parallel lines never meet, and perpendicular lines intersect at a right angle. and do not intersect in this image, but if you imagine extending both lines, they will intersect soon. So, they are neither parallel nor perpendicular.</span>