Suppose a random sample of 2100 people reveals that 1870 of them have cell phones. A)...

Suppose a random sample of 2100 people reveals that 1870 of them have cell phones.

A) Construct a 95% confidence interval for the true proportion of people who have cell phones.

B) Repeat for confidence level 99%

Expert Solution

Here, = 1870 / 2100

= 0.8904

A) Z value for 95% confidence interval = 1.96

The 95% confidence interval is = z* (1- )/n

= 0.8904 0.013

= ( 0.876 , 0.904 )

B) Z value for 99% confidence interval = 2.58

The 99% confidence interval is = z* (1- )/n

= 0.8904 0.018

= ( 0.872 , 0.907 )

orchestra answered 2 years ago

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