Answer:
1. Mean => 8.2
2. Modal class => 7 - 9
Explanation:
From the question given above, the following data were obtained:
Days >>>>>> Frequency
1 - 3 >>>>>>> 6
4 - 6 >>>>>> 8
7 - 9 >>>>>> 10
10 - 12 >>>>> 7
13 - 15 >>>>> 0
16 - 18 >>>>> 5
Next, we shall determine the the day mark.
The day mark is obtained by adding the the lower and upper class intervals and diving the result by 2.
This is illustrated below:
Days >> Day mark >>> Frequency
1 - 3 >>> 2 >>>>>>>>>> 6
4 - 6 >>> 5 >>>>>>>>> 8
7 - 9 >>> 8 >>>>>>>>> 10
10 - 12 >> 11 >>>>>>>> 7
13 - 15 >> 14 >>>>>>>> 0
16 - 18 >> 17 >>>>>>>> 5
1. Determination of the mean.
Summation of (day mark × frequency) = (2×6) + (5×8) + (8×10) + (11×7) + (14×0) +(17×5)
= 12 + 40 + 80 + 77 + 0 + 85
= 294
Summation of frequency = 6 + 8 + 10 + 7 + 0 + 5
= 36
Mean = Summation of (day mark × frequency) / Summation of frequency
Mean = 294 / 36
Mean = 8.2
2. Determination of the modal class.
The modal class is simply the class with the highest frequency.
Days >>>>>> Frequency
1 - 3 >>>>>>> 6
4 - 6 >>>>>> 8
7 - 9 >>>>>> 10
10 - 12 >>>>> 7
13 - 15 >>>>> 0
Considering the data given above, the class with the highest frequency is 7 - 9.
Thus, the modal class is => 7 - 9