# Confidence Intervals

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In random, independent samples of 225 adults and 375 teenagers who watched a certain television show... (see attached)

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##### Solution Summary

In random, independent samples of 225 adults and 375 teenagers who watched a certain television show, 146 adults and 247 teens indicated that they liked the show. Let be the proportion of all adults watching the show who liked it, and let be the proportion of all teens watching the show who liked it. Find a confidence interval for . Then complete the table below.

Carry your intermediate computations to at least three decimal places. Round your responses to at least three decimal places.

1. What is the lower limit of the 90% confidence interval? _______

2. What is the upper limit of the 90% confidence interval? _______

###### Education

- BSc , Wuhan Univ. China
- MA, Shandong Univ.

###### Recent Feedback

- "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
- "excellent work"
- "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
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- "Thank you very much for your valuable time and assistance!"

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