Confidence Intervals

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.

Mathematical Equivalence

ON

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

• (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?

Mathematical Equivalence

ON

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.

Mathematical Equivalence

ON

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

Tags

CCSS.HSS.IC.B.4

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 Margin of Error to two decimal places.

Mathematical Equivalence

ON

The lifetime of a certain type of batter is known to be normally distributed with a standard deviation of 20 hours. A sample of 50 batteries had a mean lifetime of 120.1 hours. It is desired to construct a 99% confidence interval for the mean lifetime of this type of battery. (a)  

• (114.5, 125.6)
• (112.8, 127.4)
• (112.82, 127.38)
• (114.56, 125.64)

If the 95% Confidence Interval for a population mean is (114.56, 125.54), then is it likely that the true population mean µ is greater than 130?

• Yes

• No

• Not enough information

• I have no idea what you're asking of me

Tags

CCSS.HSS.IC.A.1

CCSS.HSS.IC.B.4

A population has a standard deviation of σ = 17.3. How large of a sample must be drawn so that a 95% confidence interval for µ will have a Margin of Error equal to 1.4?

Mathematical Equivalence

ON

A person selects a random sample of 15 credit cards and determines the annual interest rate, in percent, of each one. The sample mean is 12.42 with a sample standard deviation of 1.3. It is desired to construct a 90% Confidence Interval.

Find the Standard Error to three decimal places.

• 0.336

• 0.33566

• 13.156

• 0.087

Tags

CCSS.HSS.IC.B.4