Question

The dot plots below show the ages of students belonging to two groups of salsa classes: Based on visual inspection, which group most likely has a lower mean age of salsa students? Explain your answer using two or three sentences. Make sure to use facts to support your answer. I need help with group B

Answer 1

Answer with explanation:

Group A                                                                             Group B

Age(Years)            Frequency        |             Age(Years)                  Frequency

5                              3                      |                 7                                     6

10                           4                        |                10                                     3

17                              6                      |                  14                                     4

24                             4                     |                  16                                     5

29                              3                     |                21                                      2  

Mean of grouped frequency is given by

           $=\frac{\sum(f_{i}x_{i})}{f_{i}}\\\\\text{Mean A}=\frac{5*3+10*4+17*6+24*4+29*3}{3+4+6+4+3}\\\\\text{Mean A}=\frac{15+40+102+96+87}{20}\\\\\text{Mean A}=\frac{340}{20}\\\\\text{Mean A}=17\\\\\text{Mean B}=\frac{7*6+10*3+14*4+16*5+21*2}{6+3+4+5+2}\\\\\text{Mean B}=\frac{42+30+56+80+42}{20}\\\\\text{Mean B}=\frac{260}{20}\\\\\text{Mean B}=13$

Mean of Group B is lower thanMean of Group A.

 

Answer 2

Group A:1 dot at 9:     1 x    9 =     97 dots at 10: 7 x 10 =   708 dots at 15: 8 x 15 = 1208 dots at 17: 8 x 17 = 1366 dots at 19: 6 x 19 = 114
Mean: (9+70+120+136+114) / (1+7+8+8+6) = 449/30 = 14.97
Group B:6 dots at 10: 6 x 10 = 605 dots at 14: 5 x 14 = 706 dots at 18: 6 x 18 = 1085 dots at 25: 5 x 25 = 1254 dots at 28: 4 x 28 = 1124 dots at 29: 4 x 29 = 116
mean: (60+70+108+125+112+116) / (6+5+6+5+4+4) = 591 / 30 = 19.70
The group that has a lower mean age of painting students is Group A. Its mean is 14.97 or 15 years of age.