Question

In a survey, three out of four students said that courts show too much concern for criminals. Of seventy randomly selected students

Would 68 be considered an unusually high number of students who feel that courts are partial to criminals?

Answer 1

Sample size , n =    70
Probability of an event of interest, p =   0.75

Mean = np =    70   *   0.750   =           52.500
Standard deviation = √(np(1-p)) =   √   13.1250   =               3.6228

The range rule of thumb suggests that values are unusual if they lie outside of these limits:                              
( µ ± 2σ) = (   52.5   ± 2*   3.6228   ) = (   45.25 ,   59.75 )

since, 68 is greater than upper limit , so 68 would be considered an unusually high number of students who feel that courts are partial to criminals