The average annual salary of public school teachers who graduated from a certain college is to be studied. (a) A random sample of 100 teachers has a mean of $31,678 with a standard deviation of $4,515. Construct a 99 percent confidence interval for the average salary of the population of public school teachers who graduated from this specific college. (b) Interpret in your own words what the confidence interval in (a) means.   (c) If 100 different 99 percent confidence intervals were generated, how many of them would you expect to contain the average salary of the teachers of this population?

A study of the career paths of hotel general managers sent questionnaires to an SRS of 200 hotels belonging to major U.S. hotel chains. There were 99 responses. The average time these 99 general managers had spent with their current company was 11.96 years. (Take it as known that the standard deviation of time with the company for all general managers is 3.8 years.) (a) Find the margin of error for an 85% confidence interval to estimate the mean time a general manager had spent with their current company:     years   (b) Find the margin of error for a 99% confidence interval to estimate the mean time a general manager had spent with their current company:      years

Previous surveys indicate 33% of households in Barrie regularly recycle household waste through a blue box program. In a random sample of ten households, what is the probability of finding exactly five who regularly use a blue box?

A random sample of high school seniors were asked whether they were applying for college. The resulting confidence interval for the proportion of students applying for college is (0.65,0.69). What is the margin of error?

Do AP Statistics students have higher GPA's than non AP Statistics students? Random samples of 20 AP Statistics students and 20 non AP Statistic students were taken. AP Statistics students had a mean GPA of 3.335 with a standard deviation of 0.557. Non AP Statistics students had a mean GPA of 3.04 with a standard deviation of 0.685. Assume the distribution of all AP Statistics scores are normally distributed. Use a 95% confidence interval for the true difference in average GPAS for AP Statistics and non AP Statistics students to determine if one group has a higher GPA than the other.

A study of the career paths of hotel general managers sent questionnaires to an SRS of 280 hotels belonging to major U.S. hotel chains. There were 157 responses. The average time these 157 general managers had spent with their current company was 13.28 years. (Take it as known that the standard deviation of time with the company for all general managers is 3 years.) (a) Find the margin of error for an 80% confidence interval to estimate the mean time a general manager had spent with their current company:  years (b) Find the margin of error for a 99% confidence interval to estimate the mean time a general manager had spent with their current company:  years

Researchers from a certain country were interested in how characteristics of the spleen of residents in their tropical environment compare to those found elsewhere in the world. The researchers randomly sampled 91 males and 109 females in their country. The mean and standard deviation of the spleen lengths for the males were 10.9 cm and 0.9 cm, respectively, and those for the females were 9.8 cm and 1.1 cm, respectively. Determine a 95% confidence interval for the difference between mean spleen lengths of males and females in this country. Click here to view page 1 of the table of critical values of t. Click here to view page 2 of the table of critical values of t. Let population 1 be all males in the country and let population 2 be all females in the country. The 95% confidence interval for µ1 - 4½ is ( | D (Round to three decimal places as needed. Use ascending order.)

A study by the department of education of a certain state was trying to determine the mean SAT scores of the graduating high school seniors. The study examined the scores of a random sample of 190 graduating seniors and found the mean score to be 520 with a standard deviation of 87. Determine a 95% confidence interval for the mean, rounding all values to the nearest tenth.

A study of the career paths of hotel general managers sent questionnaires to an SRS of 210 hotels belonging to major U.S. hotel chains. There were 88 responses. The average time these 88 general managers had spent with their current company was 11.73 years. (Take it as known that the standard deviation of time with the company for all general managers is 3.6 years.)

From a random sample of 48 days in a recent year, U.S. gasoline prices had a mean of $2.34 and a standard deviation of $0.32. Construct a 95% confidence interval for the population mean