Task Sets: Use data from a random sample to draw inferences about a population - Common Core Math - Grade 7

Recall / Warm-Up

In a survey, 26 out of 40 randomly selected students say they have a pet. What proportion of the sample has a pet?

$0.65$

$0.26$

$0.40$

$0.14$

A teacher wants to estimate the favorite sport of all 7th graders in her school. Which sample is most likely to give a representative estimate?

Ask the 12 students sitting near her at lunch

Survey all students in her gym class

Randomly select 30 names from the school roster

Post a sign-up sheet for anyone who wants to respond

A pollster randomly calls 200 registered voters and finds that 130 prefer Candidate A. What percent of the sample prefers Candidate A?

Fluency Practice

A random sample of 40 students shows that 26 have pets. The school has 800 students. Estimate how many students in the school have pets.

A factory's quality control team randomly tests 100 widgets and finds 4 are defective. The factory produces 10,000 widgets per day. About how many widgets per day are estimated to be defective?

A student draws 5 random samples from the same population and gets these proportions: 0.50, 0.55, 0.60, 0.65, 0.60. Which statement best describes these results?

The variation means at least one sample was collected incorrectly.

The variation is normal — different random samples naturally produce different estimates.

All 5 samples should have given exactly the same proportion.

The sample size must have been too small to get consistent results.

A researcher randomly surveys 80 city residents and finds 52 use public transit regularly. Which statement CORRECTLY reports this finding as a population inference?

65% of all city residents use public transit regularly.

Based on our sample, we estimate that about 65% of all city residents use public transit regularly.

Exactly 65 out of every 100 city residents use public transit regularly.

The survey proves that most city residents use public transit.

A librarian randomly selects 50 books from a collection of 2,000. She finds 12 need repairs. Estimate how many books in the full collection need repairs.

Drawing Inferences from Random Samples

Recall / Warm-Up

Fluency Practice