the data represent the time, in minutes, spent reading a political blog in a day. construct a frequency…

the data represent the time, in minutes, spent reading a political blog in a day. construct a frequency distribution using 5 classes. in the table, include the midpoints, relative frequencies, and cumulative frequencies. which class has the greatest frequency and which has the least frequency? complete the table, starting with the lowest class limit. (simplify your answers.) class frequency midpoint relative frequency cumulative frequency
Answer
Explanation:
Step1: Find range
The data set is (0,0,1,1,2,3,5,6,7,7,7,8,8,11,11,18,18,19). The maximum value (M = 19) and the minimum value (m=0). The range (R = M - m=19 - 0 = 19).
Step2: Determine class - width
We want 5 classes. The class - width (w=\frac{R}{n}), where (n = 5). So (w=\frac{19}{5}=3.8). We round up to (w = 4).
Step3: Define classes
The first class starts at 0. The classes are (0 - 3), (4 - 7), (8 - 11), (12 - 15), (16 - 19).
Step4: Calculate frequencies
- For the class (0 - 3): The values in this class are (0,0,1,1,2,3), so the frequency (f_1=6).
- For the class (4 - 7): The values are (5,6,7,7,7), so the frequency (f_2 = 5).
- For the class (8 - 11): The values are (8,8,11,11), so the frequency (f_3=4).
- For the class (12 - 15): There are no values in this class, so the frequency (f_4 = 0).
- For the class (16 - 19): The values are (18,18,19), so the frequency (f_5=3).
Step5: Calculate mid - points
- For the class (0 - 3), the mid - point (x_1=\frac{0 + 3}{2}=1.5).
- For the class (4 - 7), the mid - point (x_2=\frac{4+7}{2}=5.5).
- For the class (8 - 11), the mid - point (x_3=\frac{8 + 11}{2}=9.5).
- For the class (12 - 15), the mid - point (x_4=\frac{12+15}{2}=13.5).
- For the class (16 - 19), the mid - point (x_5=\frac{16 + 19}{2}=17.5).
Step6: Calculate relative frequencies
The total frequency (N=f_1 + f_2+f_3+f_4+f_5=6 + 5+4+0+3=18).
- The relative frequency for the class (0 - 3) is (rf_1=\frac{f_1}{N}=\frac{6}{18}=\frac{1}{3}).
- The relative frequency for the class (4 - 7) is (rf_2=\frac{f_2}{N}=\frac{5}{18}).
- The relative frequency for the class (8 - 11) is (rf_3=\frac{f_3}{N}=\frac{4}{18}=\frac{2}{9}).
- The relative frequency for the class (12 - 15) is (rf_4=\frac{f_4}{N}=0).
- The relative frequency for the class (16 - 19) is (rf_5=\frac{f_5}{N}=\frac{3}{18}=\frac{1}{6}).
Step7: Calculate cumulative frequencies
- The cumulative frequency for the class (0 - 3) is (cf_1=f_1 = 6).
- The cumulative frequency for the class (4 - 7) is (cf_2=f_1 + f_2=6 + 5 = 11).
- The cumulative frequency for the class (8 - 11) is (cf_3=f_1 + f_2+f_3=6 + 5+4 = 15).
- The cumulative frequency for the class (12 - 15) is (cf_4=f_1 + f_2+f_3+f_4=6 + 5+4+0 = 15).
- The cumulative frequency for the class (16 - 19) is (cf_5=f_1 + f_2+f_3+f_4+f_5=6 + 5+4+0+3 = 18).
| Class | Frequency | Mid - point | Relative Frequency | Cumulative Frequency |
|---|---|---|---|---|
| (0 - 3) | 6 | 1.5 | (\frac{1}{3}) | 6 |
| (4 - 7) | 5 | 5.5 | (\frac{5}{18}) | 11 |
| (8 - 11) | 4 | 9.5 | (\frac{2}{9}) | 15 |
| (12 - 15) | 0 | 13.5 | 0 | 15 |
| (16 - 19) | 3 | 17.5 | (\frac{1}{6}) | 18 |
The class with the greatest frequency is (0 - 3) and the class with the least frequency is (12 - 15).
Answer:
| Class | Frequency | Mid - point | Relative Frequency | Cumulative Frequency |
|---|---|---|---|---|
| (0 - 3) | 6 | 1.5 | (\frac{1}{3}) | 6 |
| (4 - 7) | 5 | 5.5 | (\frac{5}{18}) | 11 |
| (8 - 11) | 4 | 9.5 | (\frac{2}{9}) | 15 |
| (12 - 15) | 0 | 13.5 | 0 | 15 |
| (16 - 19) | 3 | 17.5 | (\frac{1}{6}) | 18 |
| The class with the greatest frequency is (0 - 3). The class with the least frequency is (12 - 15). |