IXL | Make an estimate from sample data

The manager of a 500-room hotel is replacing broken coffeemakers. He inspects 25 randomly selected rooms and finds that 1 has a broken coffeemaker.

Based on this sample, how many rooms in the hotel should the manager expect to have a broken coffeemaker?

rooms

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Learn with an example

question

A restaurant owner is redesigning her restaurant and receives a shipment of 320 new drink glasses. She checks a random sample of 16 glasses and finds that 2 are broken.

Based on this sample, how many glasses in the shipment should the restaurant owner expect to be broken?

glasses

key idea

A population is a group that is being studied. A sample is a smaller part of that group.

A random sample can be used to make inferences about an entire population.

solution

To find how many glasses in the shipment the restaurant owner should expect to be broken, you can write and solve a proportion.

In the random sample, 2 out of 16 glasses are broken. There are 320 glasses in the shipment. Let

represent the number of glasses in the shipment the restaurant owner should expect to be broken.

320

Multiply both sides by 320

320

Multiply both sides by 320

Based on the sample, the restaurant owner should expect about 40 glasses in the shipment to be broken.

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Teacher tools

Work it out

Not feeling ready yet? These can help:

L.12Solve proportions

HH.9Identify representative, random, and biased samples

GG.2Interpret line plots

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