Albert Teen

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Histograms: Finding the Frequency

# Histograms: Finding the Frequency

### Histograms: Finding the Frequency

We can work backwards from histograms to find the frequency of a given interval.

We can work backwards from a histogram to infer information and data.

Which is the correct formula for finding the frequency density?

1

Remember the formula for frequency density

When we have a histogram, or are already given the frequency density, we can rearrange this formula to give us the frequency.

2

By rearranging, we find this formula

This is useful because frequency is raw data which we can draw insight from if it is not initially provided.

1

This table describes the histogram

We have the frequency densities already, so can apply our formula to find the frequency.

2

At $0 ≤ m < 20$, the frequency is 4

The frequency density is 0.2 and the class width is 20. Therefore $0.2 \times 20 = 4$. There must have been 4 fruits between the mass of 0 and 20 grams.

3

What was the frequency at the interval $20 ≤ m < 30$

4

The frequency at $20 ≤ m < 30$ is 12

The frequency density is 1.2, while the class width is 10. Therefore, $1.2 \times 10=12$

5

What is the frequency at the interval $45 ≤ m < 60$

6

The frequency at $45 ≤ m < 60$ is 9

The frequency density is 0.6, while the class width is 15. Therefore, $0.6 \times 15=9$