Respuesta :

under 21 years of age= 40     25         20  tot= 85

between 21 and 40=     35     20         30  tot = 85

       over 40=               20     30         35   tot = 85

If one of the 255 subjects is randomly selected

P (over 40) = 85/255 = 1/3

Hope this helps!

Otras preguntas