Explanation:
In the given table, the range 140-160 mass has a frequency of 70. This means that there are 70 apples in that range.
To find the mean mass of the apples, we need to calculate the average. We can do this by adding up the products of the midpoints and frequencies of each range, and then dividing by the total number of apples.
Midpoint of 80-100 range = (80 + 100)/2 = 90
Midpoint of 100-120 range = (100 + 120)/2 = 110
Midpoint of 120-140 range = (120 + 140)/2 = 130
Midpoint of 140-160 range = (140 + 160)/2 = 150
Midpoint of 160-180 range = (160 + 180)/2 = 170
Now, let's calculate the mean mass:
Mean mass = (90 * 20 + 110 * 60 + 130 * 140 + 150 * 70 + 170 * 60) / (20 + 60 + 140 + 70 + 60)
= (1800 + 6600 + 18200 + 10500 + 10200) / 350
= 56300 / 350
= 160.857 grams (rounded to 3 decimal places)
The modal mass of the apples is the mass value that occurs most frequently. In the given table, the range 120-140 has the highest frequency of 140. Therefore, the modal mass of the apples is in the range 120-140 grams.
The upper limit of the median class can be found by calculating the cumulative frequency. The median class is the class where the cumulative frequency is equal to or greater than half of the total number of apples.
Cumulative frequency of the first class: 20
Cumulative frequency of the second class: 20 + 60 = 80
Cumulative frequency of the third class: 80 + 140 = 220
Since the cumulative frequency of the third class is greater than half of the total number of apples, the upper limit of the median class is 140 grams.
Please let me know if I am wrong.