# Which of the following are negatively correlated?

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- amount of gas left in a car’s tank and the amount of gas used
- Number of gallons of gas purchased and the amount paid for the gas.
- size of a car’s gas tank and the number of gallons it holds.
- number of miles driven and the amount of gas used.

- amount of gas left in a car’s tank and the amount of gas used
- Number of gallons of gas purchased and the amount paid for the gas.
- size of a car’s gas tank and the number of gallons it holds.
- number of miles driven and the amount of gas used.

##### 1 Answer

**The answer is 1**.

#### Explanation:

As the number of gallons of gas purchased increases, the amount paid for the gas also increases proportionately. As they rise and fall together, they are **positively correlated** .

There is **no correlation** between the size of a car’s gas tank and the number of gallons it holds. Size of the car only tells us the maximum amount (in gallons) of gas it can hold, but the amount of gas held by it may be anything between **no gas** and **full tank**.

The number of miles driven and the amount of gas used are also **positively correlated** as when one increases other also increases (except in an unfortunate circumstance of a traffic jam, when you may spend the entire gas on heating or air-conditioning or keeping the engine idle without moving at all.

The only thing that describes a **negative correlation** is the amount of gas left in a car’s tank and the amount of gas used from it as when one increases other decreases.

Hence **the answer is 1**.