Question

20% of US High School teens vape. A local High School has implemented campaigns to reduce vaping among students and believes that the percentage of students who vape at this High School is lower than the national average.   School administration implements a survey of 300 randomly selected students. They find that 51 of the 300 vape.

If the true proportion of students who vape at this school is 20%, what is the approximate probability of observing 51 or fewer vapers in a random sample of 300?

Group of answer choices

.05

.10

.20

.15

Answer 1

Given : n=300 , p=0.20 , q=1-p=1-0.20=0.80

Here , np=300*0.20=60> 10 and nq=300*0.80=240>10

Therefore , use the normal approximation,

standard deviation=

Now ,

=0.0968 it is approximately 0.1

Therefore , the approximate probability of observing 51 or fewer vapors in a random sample of 300 is 0.0968.

round the probability to one decimal place we get 0.1

#Ans option 2 nd is correct