## Making Inferences From Random Data

#### Aligned To Common Core Standard:

**Grade 7 Statistics** - 7.G.SP.A.2

How to make Inferences from Random Data? Students start developing inferences from random data throughout the 7th and 8th standard. It is one of the things that students should learn. Students are given random data for making population inferences. Any random data is a subset of the population. Random samples are more likely to contain data that can later be used for making probable predictions for the entire population. The size of the population determines the strength of the inference. For example, the larger the sample size, the stronger will be the inference. For example, a home builder surveyed 50 customers to find out how (i.e., through which medium) people have heard about their business. Solution: If the circle incorporates the entire population of 110,000 people and the builder should only need to choose one type of marketing for the next year, which option should he choose and why? Based on this random sampling, the strength of the inference can be weak because there are only 50 customers out of the entire population size where the city was surveyed. Based on this quantitative description, it is most likely that the builder will choose "friend referral" because half the surveyed customers found out about the builder from the friends. This selection of worksheets and lessons will help you learn to make well thought out decisions based on data that is collected.

### Printable Worksheets And Lessons

- Ape Population Step-by-step
Lesson- This is why they tag animals in the wild.

- Guided Lesson
- We go from alligators to cafeteria menus to tracking chips in
this one.

- Guided Lesson Explanation
- This is a really good skill to work on. I find it useful for students.

- Practice Worksheet
- This one took a long time to write. It will also take a long time
to complete.

- Matching Worksheet - Match the problems to the numbers present.

#### Homework Sheets

Students that see this for the first time always say things like, "That is how National Geographic does it!"

- Homework 1 - Troy has to complete a research project on the African Elephant population in Africa. He is trying to estimate the size and population of African Elephants. He randomly catches 25 African Elephants and tags them. He releases the elephants into the jungle. A few days later, he observed 100 African Elephants, 15 of which were tagged.
- Homework 2 - The School Health Department wants to open a cafeteria in the school. So they collected data from two random samples of 100 students regarding student s lunch preference? Make at least two inferences based on the results.
- Homework 3 - A hardware company wants to test their hardware. They tagged 25 pieces. The following year, 150 pieces are returned and found that 18 were tagged. What is the best estimation of the hardware sales?

#### Practice Worksheets

Time to focus on data that is already collected.

- Practice 1 - The animal department wants to estimate the kangaroo population. So they marked 30 kangaroos with paint. These kangaroos were then released into the jungle. After four months 600 kangaroos were caught. Among these Kangaroo, 18 were marked. To the nearest whole number, what is the best estimate for the kangaroo population?
- Practice 2 - Sara collected two random samples of 100 children regarding their favorite cartoon. Make at least two inferences based on the results.
- Practice 3 - The government of Russia declared Siberian Tiger as an endangered animal. They tied a belt around the legs of 20 Siberian Tigers and released them. A year later, they found 160 Siberian Tigers; among those Siberian Tigers, 16 had belts. Find the best estimate for the population?

#### Math Skill Quizzes

Very wordy problems result in less problems per page.

- Quiz 1 - Edward was given a project to research the leopard population in Spain. He randomly catches 44 leopards and marks them with paint. He releases the leopards in the jungle. The following year he observes 220 leopards and he found that 11 were marked with the paint that he used. Find out the best estimate for the size of the leopard population?
- Quiz 2 - Gerald collected two random samples of 100 women regarding their favorite color of folder. Make an inference from the data.
- Quiz 3 - A famous television channel put tags on 48 butterflies and released them. Later, they catch 450 butterflies; among those 24 were tagged. Calculate the best estimate for the butterfly population?