Question

Use the given data to construct a 90% confidence interval for the population proportion p. x=50, n= 70 Round the answer to at least three decimal places. The confidence interval is ne crise mora = (ID. Exo

Answer 1

Solution :

=> Answer :- The confidence interval is (0.625 , 0.803)

Given that x = 50, n = 70

=> proportion p = x/n

= 50/70

= 0.7143

= 0.714 (rounded)

=> q = 1 - p = 0.286

=> for 90% confidence interval, Z = 1.645

=> A 90% confidence interval of the population proportion is

=> p +/- Z*sqrt(p*q/n)

=> 0.714 +/- 1.645*sqrt(0.714*0.286/70)

=> (0.6252 , 0.8028)

=> (0.625 , 0.803) (rounded)

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Solution :

Given that n = 246, x = 105

(a)
=> The point estimate for the proportion of cell phone owners aged 18 - 24 who have an android phone is

=> p = x/n

= 105/246

= 0.4268

= 0.427 (rounded)