Estimate a population from a sample survey, with the margin of error given
Grade 9 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.
Esme compared random-sample surveys of weekly reading time. Grade 7: 6.2 hours, margin of error 0.5. Grade 8: 5.8 hours, margin of error 0.6. Which conclusion fits?
- Grade 7 is higher, because 6.2 hours is more than 5.8 hours.
- The two are equal, because the intervals overlap.
- We can't be sure which is higher: the intervals overlap.
Jun compared random-sample surveys of percent who bike to school. Oak School: 50%, margin of error 5 points. Elm School: 44%, margin of error 6 points. Which conclusion fits?
Two number lines, one above the other, each with a dot at its sample result (50% and 44%) and a bar for its margin of error (not to scale). Two number lines, one above the other, each with a dot at its sample result (50% and 44%) and a bar for its margin of error (not to scale). Oak School 0 10 20 30 40 50 60 70 80 90 100 margin of error 50% % Elm School 0 10 20 30 40 50 60 70 80 90 100 margin of error 44% % - We can't be sure which is higher: the intervals overlap.
- Oak School is higher, because 50% is more than 44%, so the gap is real.
- The two are equal, because the intervals overlap.
Kira compared random-sample surveys of nightly sleep. The chess club: 7.9 hours, margin of error 0.3. The art club: 7.1 hours, margin of error 0.4. Which conclusion fits?
Two number lines, one above the other, each with a dot at its sample result (7.9 hours and 7.1 hours) and a bar for its margin of error (not to scale). Two number lines, one above the other, each with a dot at its sample result (7.9 hours and 7.1 hours) and a bar for its margin of error (not to scale). 7.9 hours 0 1 2 3 4 5 6 7 8 9 10 Not to scale. 7.1 hours 0 1 2 3 4 5 6 7 8 9 10 Not to scale. - We can't tell, because a sample is never exact.
- The chess club is likely higher: even its lowest estimate is above the art club's highest.
- The art club is likely higher, because its margin of error is much bigger than the chess club's.
A random sample of 300 of Milo's school's 1500 students found 40% walk to school, margin of error 6 percentage points. How many more students is the highest estimate than the lowest?
Number line with a dot at the sample result, 40%, and a bar for the margin of error (not to scale; its ends are not labeled). Number line with a dot at the sample result, 40%, and a bar for the margin of error (not to scale; its ends are not labeled). margin of error 40% Not to scale. A random sample of 400 of Noah's school's 2400 students found 25% play an instrument, margin of error 4 percentage points. How many more students is the highest estimate than the lowest?
Number line with a dot at the sample result, 25%, and a bar for the margin of error (not to scale; its ends are not labeled). Number line with a dot at the sample result, 25%, and a bar for the margin of error (not to scale; its ends are not labeled). 0 25 50 75 100 margin of error sample result, 25% percent Not to scale. A random sample of 120 of Pia's school's 600 students averaged 4.5 books read last month, margin of error 0.4. How much greater is the highest estimate of the school's total than the lowest?
Number line with a dot at the sample result, 4.5, and a bar for the margin of error (not to scale; its ends are not labeled). Number line with a dot at the sample result, 4.5, and a bar for the margin of error (not to scale; its ends are not labeled). 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 margin of error sample result Not to scale. A random sample of 100 of Ren's school's 900 students averaged 2.5 hours of homework a week, margin of error 0.3. How much greater is the highest estimate of the school's total than the lowest?
Number line with a dot at the sample result, 2.5, and a bar for the margin of error (not to scale; its ends are not labeled). Number line with a dot at the sample result, 2.5, and a bar for the margin of error (not to scale; its ends are not labeled). 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 margin of error sample result Not to scale. From a random sample, Tala's report says 52% to 64% of all students want a garden club. That is the sample result ± the margin of error. What is the margin of error?
Number line with a bar from 52% to 64%; the middle of the bar is not marked (not to scale). Number line with a bar from 52% to 64%; the middle of the bar is not marked (not to scale). 60 bar Not to scale. From a random sample, Zee's report says the students' mean outdoor play is 5.4 to 6.2 hours a week. That is the sample mean ± the margin of error. What is the margin of error?
Number line with a bar from 5.4 to 6.2; the middle of the bar is not marked (not to scale). Number line with a bar from 5.4 to 6.2; the middle of the bar is not marked (not to scale). 5 5.2 5.4 5.6 5.8 6 6.2 6.4 6.6 6.8 7 Not to scale. From a random sample, Ari's report says 31% to 39% of all students visit the library each week. That is the sample result ± the margin of error. What is the margin of error?
Number line with a bar from 31% to 39%; the middle of the bar is not marked (not to scale). Number line with a bar from 31% to 39%; the middle of the bar is not marked (not to scale). 0 10 20 30 40 50 60 70 80 90 100 31% 39% percent the middle of the bar is not marked (not to scale)