Question

Smoking Based on a recent Harris Interactive survey, 20% of adults in the United States smoke. In a survey of 50 statistics students, it is found that 6 of them smoke. Find the probability that should be used for determining whether the 20% rate is correct for statistics students.

Group of answer choices

a. 0.2907

b. -0.2709

c. 0.02709

d. 0.1075

Answer 1

Answer)

Null hypothesis Ho : P = 0.2

Alternate hypothesis Ha : P not equal to 0.2

N = 50

First we need to check the conditions of normality that is if n*p and n*(1-p) both are greater than 5 or not

N*p = 10

N*(1-p) = 40

Both the conditions are met so we can use standard normal z table to estimate the P-Value.

Test statistics z = (oberved p - claimed p)/standard error.

Standard error = √{claimed p*(1-claimed p)/√n.

After substitution,

Z = -1.41

From z table, P(z<-1.41) = 0.0793

Since the test is two tailed,

Probability = 2*0.0793 = 0.1586

Closest is 0.1075