Exam 8: Interval Estimation

A random sample of 64 students at a university showed an average age of 25 years and a sample standard deviation of 2 years. The 95% confidence interval for the true average age of all students in the university is

The t distribution is a family of similar probability distributions, with each individual distribution depending on a parameter known as the​

In November 2018, 50,000 people living in the United States were asked whether they had a computer at home. 43,128 answered yes, they had a computer at home. There were 326,766,748 people living in the United States at the time of the survey. Determine an interval with 99% confidence for the number (how many) of people living in the United States who have a computer at home.

When s is used to estimate σ, the margin of error is computed by using the

In interval estimation, the t distribution is applicable only when the

A random sample of 64 observations has a mean of 20, a median of 21, and a mode of 22. The population standard deviation is known to equal 4.8. The 95.44% confidence interval for the population mean is

The t distribution should be used whenever the

The following random sample from a population whose values were normally distributed was collected. 10 8 11 11 ​ The 95% confidence interval for μ is

In 2015, approximately 136,943,000 people visited an emergency room in the United States. Of these, approximately 12,263,000 were subsequently admitted to the hospital. Determine an interval with 99% confidence for the number (how many) of people visiting an emergency room who were subsequently admitted to the hospital.

Potential sampling error _____as the sample size increases.

A sample of 100 information systems managers had an average hourly income of $40.00 with a standard deviation of $8.00. The 95% confidence interval for the average hourly wage (in $) of all information system managers is

A sample of 200 elements from a population with a known standard deviation is selected. For an interval estimation of μ, the proper distribution to use is the

A random sample of 64 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 240. The margin of error at 95% confidence is

The value added to and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient will be

In developing an interval estimate, if the population standard deviation is unknown,

It is known that the population variance (σ²) is 125. At 95% confidence, what sample size should be taken so that the margin of error does not exceed 3?

A random sample of 25,000 ACT test takers had an average score of 21 with a standard deviation of 5. With a .95 probability, determine the margin of error.

We can reduce the margin of error in an interval estimate of p by doing any of the following except​

A random sample of 81 SAT scores of students applying for merit scholarships showed an average of 1400 with a standard deviation of 300. The t value needed to develop the 95% confidence interval for the population mean SAT score is