Problem-Solving and Data AnalysisMediumEstimating a population count from a sample proportion
Problem-Solving and Data Analysis practice question
A wildlife officer catches a random sample of 60 fish from a pond and finds that 18 of them are carp. If the pond holds about 1,200 fish, what is the best estimate of the number of carp in the pond?
Answer: 360
The sample proportion is 18/60 = 0.3, so the estimate is 0.3 × 1,200 = 360.
Common wrong answers
- If you answered 18
- 18 is the number of carp in the SAMPLE.
- If you answered 72
- 72 is 18 × 4, scaling by the wrong factor; the pond is 20 times the sample (1,200 ÷ 60), so 18 × 20 = 360.
- If you answered 400
- 400 uses a third instead of 18/60 = 0.3.
More Problem-Solving and Data Analysis questions
- Medium
A car travels 150 miles in 2.5 hours. At this rate, how far will it travel in 4 hours? - Medium
The price of a stock rises from $40 to $50. What is the percent increase? - Medium
Based on the model, what score does the line predict for a student who studies 5 hours? - Medium
A population decreases from 250 to 200 over a year. What is the percent decrease? - Medium
If one person is chosen at random from those who prefer tea, what is the probability the person is under 30? - Medium
What is the difference between the mean and the median of this data set?
Not affiliated with the College Board. SAT is a trademark of the College Board.