Question

Refer to the accompanying data set and use the 25 home voltage measurements to construct a frequency distribution with five classes. Begin with a lower class limit of 125.5 ​volts, and use a class width of 0.2 volt. Does the result appear to have a normal​ distribution? Why or why​ not? LOADING... Click the icon to view the data. Complete the frequency distribution below. Voltage​ (volts) Frequency 125.5minus nothing nothing nothingminus nothing nothing nothingminus nothing nothing nothingminus nothing nothing nothingminus nothing nothing ​(Type integers or decimals rounded to the nearest tenth as​ needed.) Does the result appear to have a normal​ distribution? Why or why​ not? A. No comma because the frequencies are roughly equal across the voltage classes. B. ​Yes, because the frequencies are roughly equal across the voltage classes. C. ​No, because the frequencies are randomly distributed. D. Yes comma because the frequencies start low comma reach a maximum comma then become low again comma and are roughly symmetric about the maximum frequency. E. ​No, because the frequencies are not equal across the voltage classes.

Answer 1

Correct Answer:  A. No, because the frequencies are roughly equal across the voltage classes.

From the data points,

Day	Home (volts)	Day	Home (volts)	Day	Home (volts)	Day	Home (volts)
1	125.8	8	125.8	15	126.2	22	126.3
2	125.6	9	125.5	16	126.2	23	126.3
3	125.9	10	126.2	17	126	24	125.7
4	126.2	11	126	18	125.7	25	126
5	126.3	12	126.3	19	125.6
6	125.5	13	125.9	20	126.4
7	125.5	14	125.7	21	126.2

The five classes and their frequency distribution are,

Voltage (volts)	Frequency
125.5-125.6	5
125.7-125.8	5
125.9-126	5
126.1-126.2	5
126.3-126.4	5

Since the frequencies are equal across all the classes (uniformly distribution), voltages are not normally distributed.