Answer:
(0.3049 ; 0.3751)
Explanation:
The confidence interval for proportion can be obtained using the relation :
Phat ± Zcritical * [√phat(1-phat) / n]
phat = x / n
Sample size, n = 700
x = 238
phat = 238/700 = 0.34
Zcritical at 95% = 1.96
C.I = 0.34 ± 1.96 * [√0.34(1-0.34) / 700]
C.I = 0.34 ± 1.96 * 0.0179045
C. I = 0.34 ± 0.0350928
Lower boundary = 0.34 - 0.0350928 = 0.3049
Upper boundary = 0.34 + 0.0350928 = 0.37509
(0.3049 ; 0.3751)