Answer: 0.9984224
Step-by-step explanation:
Let p is the proportion of cell phone owners who used their phone to text.
Given : The probability of cell phone owners who used their cell phone to send or receive text messages was : p= 0.80
sample size : n= 1000
Then, the the probability that [tex]\hat{p}[/tex] was between 0.76 and 0.84 will be :-
[tex]P(0.76<p<0.84)=P(\dfrac{0.76-0.80}{\sqrt{\dfrac{0.80(0.20)}{1000}}}<\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}< \dfrac{0.84-0.80}{\sqrt{\dfrac{0.80(0.20)}{1000}}} )\\\\=P(-3.16<z< 3.16)=1-2P(z>3.16)\ \ [\because P(-z<Z<z)=1-2P(Z>|z|)]\\\\=1-2(0.0007888)=0.9984224[/tex]
Hence, the required probability = 0.9984224