To determine the sample size $n$ for the data set, we need to sum the frequencies of all the bars in the histogram. Observing the histogram:

• 60-64: Frequency = 1
• 64-68: Frequency = 2
• 68-72: Frequency = 7
• 72-76: Frequency = 12
• 76-80: Frequency = 8
• 80-84: Frequency = 5
• 84-88: Frequency = 4

Now, add up the frequencies:
$1 + 2 + 7 + 12 + 8 + 5 + 4 = 39$

Thus, the sample size $n$ is 39.

Let me know if you need further clarification or explanations!

Here are related questions you might explore:

1. What is the mode of this data set?
2. How would you calculate the mean amount of sugar for this data?
3. What is the range of the sugar amounts in the data set?
4. Can you identify which interval has the highest frequency?
5. How do you calculate the median using a histogram?

Tip: When reading histograms, always sum the frequencies to find the total sample size.