Option 1 and 3 are correct. The given graph is formed between the relative frequency and time.
How do One determine the relative frequency?
The relative frequency is the ratio of the count of the considered subgroup to the total count. The frequency of the considered subgroup in relation to the total frequency is relative frequency.
The statements are true as follows;
1. To be a density curve, the area between the x-axis and the curve must be 1.
3. This could be a density curve because all points on the curve are above the x-axis.
Option 1 and 3 are correct.
Learn more about conditional relative frequency refer:
https://brainly.com/question/8358304
#SPJ2