Miss Lopez is considering two different design companies to order shirts from for spirit week in June custom ink charges $9.65 p
1 answer:
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Answer:
0.025 ;
(-0.7198 ; 0.7698)
Step-by-step explanation:
From the table :
_____________ private schls ___ public schls
Sample size, n _____ 80 __________ 520
P, NBC teachers ___ 0.175 ________ 0.150
P1 = P of private school teachers
P2 = P of public school teachers
Difference in proportion :
P1 - P12 = 0.175 - 0.150.= 0.025
The 90% confidence interval for 2 - sample proportion :
C.I = (p1-p2) ± [Zcritical * √(p1(1-p1)/n1 + (p2(1-p2)/n2)]
Zcritical at 90% = 1.645
C.I = 0.025 ± [1.645 * √((0.175*0.825)/80 + (0.150*0.850)/520)]
C.I = 0.025 ± [1.645 * √(0.0018046875 + 0.0002451)]
C.I = 0.025 ± 1.645 * 0.0452755
C.I = 0.025 ± 0.07448
C.I = (-0.7198 ; 0.7698)
