Question

20. 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?

	A.	The correct answer is not among the choices.
	B.	Yes, because P(X ≥ 68) ≤ .05
	C.	Yes, because P(X ≤ 68) ≤ .05
	D.	No,because P(X≥68)≤.05
	E.	No,because P(X≤68)≤.05

21.

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

Would it be unusually low if we observed thirty of seventy students who feel that courts are partial to criminals?

	A.	No,because P(X≤30)≤.05
	B.	No,because P(X≥30)≤.05
	C.	Yes, because P(X ≤ 30) ≤ .05
	D.	The correct answer is not among the choices.
	E.	Yes,because P(X≥30)≤.05

Answer 1

20. Let X bet the random variable denoting the number of students who feel that courts are partial to criminals.

Given, in a survey of 3 of 4 students said the courts show too much concern for criminals.

Therefore the probability of success,

Now out of 70 randomly selected students 68 students feel that courts are partial to criminals, to test if it is an unusually high number of students. We find P(X ≥68) i.e. probability that 68 or more students out of 70 feel that courts are partial to criminals.

By binomial probability law :

Now,

Answer: B) Yes, because P(X ≥ 68) ≤ .05

21. Out of 70 randomly selected students 30 students feel that courts are partial to criminals, to test if it is an unusually low number of students. We find P(X  ≤ 30) i.e. probability that 30 or less students out of 70 feel that courts are partial to criminals.

  

Answer: C) Yes, because P(X ≤ 30) ≤ .05