Respuesta :

chikafujiwara

Answer:

[tex]15.23[/tex]

Step-by-step explanation:

First, we can make an equation by adding all the ages together and dividing it by the sum of the frequencies.

[tex](13*7)+(14*12)+(15*18)+(16*9)+(17*5)+(18*4)+(19*2)[/tex]

Now simplify.

[tex](13*7)+(14*12)+(15*18)+(16*9)+(17*5)+(18*4)+(19*2) = 868[/tex]

We can divide this number by the sum of the frequencies.

[tex]\frac{868}{7+12+18+9+5+4+2} \\ \\ \frac{868}{57} \\ \\ 15.23[/tex]

jcherry99

Answer:

Step-by-step explanation:

First you need to find the total number of years of all the people tracked.

The general formula is

Total years = age*frequency for all ages.

Age                 Frequency              Total

13                        7                             91

14                       12                           168

15                       18                           270

16                        9                            144

17                         5                             85

18                         4                             72

19                         2                             38

Totals                 57                            868

The mean is the total number of years / total frequency

mean = 868/57

mean = 15.23