Albert Teen YOU ARE LEARNING:  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, $0.6 \times 15=9$ 