Confidence Intervals and Hypothesis Testing

What is the primary purpose of a confidence interval for a mean?

• to estimate a sample mean

• to test a hypothesis about a sample mean

• to estimate a population mean

• to provide an interval that covers 95% of the individual values in the population

The value of z selected for constructing a confidence interval is called the ______________ value.

• error

• confidence

• student

• critical

• Margin of error

• Point estimate

• Standard Error

• Confidence Interval

What is the critical z-value for an 85% confidence interval?

• 0.8023

• 1.44

• 1.04

• 2.3

Find the Critical Value for an 86% Confidence Level.

• 1.53

• 1.48

• 1.282

• 2.11

A sample size of n = 64 is drawn from a population whose standard deviation is σ = 5.6.

Find the margin of error for a 99% confidence interval for µ.

• 1.799

• 1.798

• 1.803

A large sample has mean of 7.1 and Standard Error of 2.3.

Construct a 90% Confidence Interval for the population mean µ (to two decimal places).

• (3.32, 10.88)

• (3.8, 7.1)

• (3.3, 10.9)

• (3.3165, 10.8835)

An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.

What is the point estimate?

• 75

• 105.2

• 10

• 0.90

An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.

Find the critical value.

• 0.90

• 1.155

• 1.645

• 1.283

An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.

Find the Standard Error.

• 75

• 10

• 105.2

• 1.155