For a sinlge sample of n=23, the t values used to determine the 90% confidence interval are

The mean replacement time for a random sample of 20 washing machines is 9.9 years and the standard deviation is 2.4 years. Construct a 99% confidence interval for the standard deviation, σ, of the replacement times of all washing machines of this type.

In a random sample of 392 people that were tested for the Norcovirus, it was found that 314 did not have the virus. A 97% confidence interval was constructed to estimate the proportion of the population that does not have the Norcovirus. This confidence interval came out to be (0.76,0.84).

A random sample of n₁ = 261 people who live in a city were selected and 107 identified as a "dog person." A random sample of n2 = 107 people who live in a rural area were selected and 62 identified as a "dog person." Find the 99% confidence interval for the difference in the proportion of people that live in a city who identify as a "dog person" and the proportion of people that live in a rural area who identify as a "dog person." Round answers to to 4 decimal places. P1-P2< Question Help: Message instructor Submit Question

A random sample of n₁ = 217 people who live in a city were selected and 106 identified as a "dog person." A random sample of n₂ = 114 people who live in a rural area were selected and 66 identified as a "dog person." Find the 90% confidence interval for the difference in the proportion of people that live in a city who identify as a "dog person" and the proportion of people that live in a rural area who identify as a "dog person." Round answers to to 4 decimal places. < P1 P2 <

In a survey funded by the UW school of medicine, 750 of 1,000 adult Seattle residents said they did not believe they could contract a sexually transmitted infection (STI) and 893 of 1,123 Denver residents said they did not believe they could contract an (STI). Construct a 95% confidence interval of the difference in proportions of Seattle and Denver residents who do not believe they could contract a STI. (Use a z score of 1.96 for your computations.) O (.0809, .0095) O (.0809, -.0095) O (-.0809, .0095) O (-.0095, .0809)

A sample size of 100 from a population having a standard deviation =8 produced a mean of 40. The 99% confidence interval for the population mean (rounded to two decimals) is:

A random sample of n1 = 213 people who live in a city were selected and 80 identified as a "dog person." A random sample of n2 = 98 people who live in a rural area were selected and 61 identified as a "dog person." Find the 90% confidence interval for the difference in the proportion of people that live in a city who identify as a "dog person" and the proportion of people that live in a rural area who identify as a "dog person." Round answers to to 4 decimal places. Рі — Р2

find the t sub alpha/2 when n=23 for the 95% confidence interval.

For a 95% confidence interval and n=21 give the Chi-squared right value.