1.A smart phone manufacturer is interested in constructing a 95% confidence interval for the proportion of smart phones that break before the warranty expires. 95 of the 1608 randomly selected smart phones broke before the warranty expired. Round answers to 4 decimal places where possible.
a. With 95% confidence the proportion of all smart phones that break before the warranty expires is between and .
b. If many groups of 1608 randomly selected smart phones are selected, then a different confidence interval would be produced for each group. About percent of these confidence intervals will contain the true population proportion of all smart phones that break before the warranty expires and about percent will not contain the true population proportion.
2.You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately p = 0.82. You would like to be 96% confident that your esimate is within 2% of the true population proportion. How large of a sample size is required?
3.Suppose we want to estimate the proportion of teenagers (aged 13-18) who are lactose intolerant. If we want to estimate this proportion to within 5% at the 95% confidence level, how many randomly selected teenagers must we survey?
Already registered? Login
Not Account? Sign up
Enter your email address to reset your password
Back to Login? Click here