Random Sampling
Grade 7 · Math · Probability and Statistics · Quebec, Canada
Lesson Summary
Learn how to collect a fair sample and use it to make predictions about a larger group.
Explanation
A random sample is a subset of a population chosen so that every member has an equal chance of being selected. Random sampling reduces bias and makes your results more trustworthy. Once you have sample data, you can use proportions to estimate facts about the whole population. For example, if 30 out of 100 surveyed students prefer pizza, you can estimate that about 30% of all students prefer pizza.
Practice Questions
Q1: You survey 50 students and 20 say they walk to school. There are 400 students total. Estimate how many walk to school.
Answer: 20/50 = 0.4. 0.4 × 400 = 160 students.
Q2: Why is it important that a sample is random?
Answer: A random sample is more likely to represent the whole population fairly because every member has an equal chance of being chosen, reducing bias.
Q3: A biologist catches 40 fish, tags them, and releases them. Later she catches 50 fish and 8 are tagged. Estimate the total fish in the lake.
Answer: Set up the proportion 8/50 = 40/N. Cross-multiply: 8N = 2000, so N = 250 fish.
People Also Ask
What is Random Sampling in Grade 7 Math?+
Random Sampling is a lesson in the Probability and Statistics chapter of Grade 7 Math. It is part of the Quebec, Canada school curriculum and covers key concepts that students need to understand at this level.
What grade level covers Random Sampling?+
Random Sampling is taught in Grade 7 as part of the Math curriculum in Quebec, Canada.
How can I help my child with Probability and Statistics in Math?+
Start with the lesson summary and explanation on this page. Practice the questions provided, then use TutorTom for personalized, step-by-step help with Probability and Statistics topics.