In: Statistics and Probability
In a random poll of 801 Americans around the country, 57% of them have some form of streaming service. Create and interpret a 90% confidence interval for the percentage of Americans who use a streaming service using PANIC.
Solution :
Given that,
n = 801
Point estimate = sample proportion = =57%=0.57
1 - = 1- 0.57 =0.43
At 90% confidence level
= 1 - 90%
= 1 - 0.90 =0.10
/2
= 0.05
Z/2
= Z 0.05 = 1.645 ( Using z table )
Margin of error = E Z/2 *(( * (1 - )) / n)
= 1.645 *((0.57*0.43) / 801)
E = 0.029
A 90% confidence interval for population proportion p is ,
- E < p < + E
0.57-0.029 < p < 0.57+0.029
0.541< p < 0.599