Final answer:
To estimate the mean, we find the midpoint of each interval and multiply it by the corresponding frequency. We then sum up the products and divide by the total frequency.
Step-by-step explanation:
To estimate the mean of the number of seals spotted in the ocean, we need to find the midpoint of each interval and multiply it by its corresponding frequency. Then, we sum up the products and divide it by the total frequency. For the given grouped frequency, the midpoint and frequency values are as follows:
- Midpoint: 2.5, Frequency: 3
- Midpoint: 9.5, Frequency: 8
- Midpoint: 8.5, Frequency: 11
- Midpoint: 19.5, Frequency: 4
Next, we calculate the sum of the products:
(2.5 * 3) + (9.5 * 8) + (8.5 * 11) + (19.5 * 4) = 28 + 76 + 93.5 + 78 = 275.5
Finally, we divide the sum by the total frequency:
275.5 ÷ (3 + 8 + 11 + 4) = 275.5 ÷ 26 = 10.596
Therefore, the estimated mean of the number of seals spotted in the ocean by randomly selected visitors is approximately 10.6.