Answer:
The correct option is C.
Step-by-step explanation:
In a dot plot, the number of dots above a number represents the frequency of that number.
From the given dot plot it is clear that number of dots for group R is 21 and the time taken by the students of groups R are
45, 50, 50, 55, 60, 60, 70, 75, 80, 85, 90, 90, 95, 100, 100, 105, 110, 110, 115, 120, 120
The average of the data is
[tex]Average=\frac{\sum x}{n}[/tex]
[tex]Average=\frac{45+50+50+55+60+60+70+75+80+85+90+90+95+100+100+105+110+110+115+120+120}{21}[/tex]
[tex]Average=\frac{1785}{21}[/tex]
[tex]Average=85[/tex]
From the given dot plot it is clear that number of dots for group S is 17 and the time taken by the students of groups S are
50, 55, 60, 60, 65, 70, 70, 80, 90, 90, 95, 100, 105, 110, 110, 115, 120
[tex]Average=\frac{50+55+60+60+65+70+70+80+90+90+95+100+105+110+110+115+120}{17}[/tex]
[tex]Average=\frac{1445}{17}[/tex]
[tex]Average=85[/tex]
The average time of both groups are same.
Since both groups show about the same average time, therefore the correct option is C.
