Question

Dr. Garcia is interested in evaluating the proportion of all Aggie undergraduates who get less than 8 hours of sleep per night. She conducted a survey of 100 undergraduates at Texas A&M and found that 60 of them get less than 8 hours of sleep per night.

Provide a 90% confidence internal of the population proportion.

Answers:

0.6 +/- 1.645 s /100 where s is the sample standard deviation of sleep

0.6 +/- 0.081

0.6 +/- 0.096

0.6 +/- 0.004

0.6+/- 0.006

Answer 1

Solution :

Given that,

Point estimate = sample proportion = = x / n = 60 / 100 = 0.6

1 - = 0.4

Z/2 = 1.645

Margin of error = E = Z / 2 * (( * (1 - )) / n)

= 1.645 * ((0.6 * 0.4) / 100)

= 0.081

A 90% confidence interval for population proportion p is ,

0.6 +/- 0.081

(0.519, 0.681)