Confidence Interval

A sample of 20 cupcakes found the interval for average calories to be (150, 350). Which is the correct interpretation of the 95% confidence interval?

• We are 95% confident that the true mean caloric content can be found with a sample of 150 to 350 cupcakes.

• We are 95% confident that the interval (150, 350) captures the true average caloric content.

• We are 95% confident that a sample of 20 cupcakes will find 250 calories per cupcake.

• None of these are correct.

Tags

CCSS.HSS.IC.B.4

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.

What is the Confidence Interval to one decimal place?

• (114.5, 125.6)

• (112.8, 127.4)

• (112.82, 127.38)

• (114.56, 125.64)

Tags

CCSS.HSS.IC.B.4

Find the confidence interval for a mean of 142.5 and a margin of error of 5.2.

• (5.2, 142.5)

• (137.5, 142.5)

• (142.5, 147.5)

• (137.3, 147.7)

Tags

CCSS.HSS.IC.B.4

If using a 95% confidence level, what value of z should you use?

Tags

CCSS.HSS.ID.A.4

Which symbol represents the mean of a sample?

If using a 99% confidence level, what value of z should you use?

Tags

CCSS.HSS.ID.A.4

What can you do to reduce the margin of error? 

• increase the confidence level
• decrease the confidence level
• increase sample size
• decrease sample size

Tags

CCSS.HSS.IC.B.4

4010 people were surveyed concerning their thoughts on the upcoming election. What was the margin of error?

Tags

CCSS.HSS.IC.B.4

A research team surveys 1001 adults, asking them how many hours they work per week. What is the margin of error for this survey?

• 3%

• 32%

• 63%

• 9%

Tags

CCSS.HSS.IC.B.4

Your city is electing a new mayor and you surveyed 300 people where 55% of them said they will will vote for candidate A. Using the margin of error, between what range should the candidate A expect in percentage of votes this election?

• 49.2% and 60.8%

• 49.2% and 60.2%

• 48.2% and 61.8%

• 59.2% and 65.8%

Tags

CCSS.HSS.IC.B.4