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.

no association

step-by-step explanation:

if you have eyes and you can use them efficiently you can see that it just looks like random dots like do a line of best fit and like they're so spread out it's such a weak association you might as well consider it nonexistent