You are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. From a random sample of 74 dates, the mean record high daily temperature in a certain city has a mean of 85.22 degrees F. Assume the population standard deviation is 13.97 degrees F.

Very confused! at 95% confidence level, the true population mean will be between 134.33 and 145.67.

Step-by-step explanation:

A random sample of 45 home theater systems has a mean price of $140.00

Assume the population standard deviation is $19.40

population standard deviation is 19.40

sample size is 45.

standard error of the sample mean is 19.40 / sqrt(45) = 2.89198

at 90% confidence level, critical z is plus or minus 1.645.

at 95% confidence level, critical z is plus or minus 1.96.

critical raw score will be sample mean plus or minus critical z-score * standard error of the mean.

your sample mean is 140.

your standard error of the mean is 2.89198

at 90% confidence level, your critical raw score will be 140 plus or minus 1.645 * 2.89198.

that becomes 140 plus or minus 4.76 rounded to the nearest penny.

at 90% confidence level, the true population mean will be between 135.24 and 144.76.

at 95% confidence level, your critical raw score will be 140 plus or minus 1.96 * 2.89198.

that becomes 140 plus or minus 5.67 rounded to the nearest penny.

incomplete question. how do you expect anyone to you when you do not post the question in its entirety?

answer:      

step-by-step explanation: