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WorksheetsPoint Estimates and Margin of Error
Total questions: 14
Worksheet time: 7mins
A confidence interval gives all plausible values of the population parameter you are trying to estimate
TRUE
FALSE
I HAVE NO IDEA
How do you interpret a confidence interval?
There is a 95% chance the the interval from ____ to ____ contains the population parameter.
95% of the data values are in the interval from _____ to _____.
I am 95% confident that the interval from _____ to _____ captures the true value of the population parameter.
I am 95% confident that the sample statistic is in the interval from _____ to _____.
The general form of a confidence interval is
point estimate x 2
point estimate + margin of error
point estimate - margin of error
point estimate +/- margin of error
Given a confidence interval, how do you determine the value of the point estimate?
Find the middle of the interval - (lower value + upper value)/2.
Find the range of the interval and divide by 2.
Use the lower end of the interval.
You can't determine the point estimate from the confidence interval.
If a proposed value of the population parameter is not captured in the confidence interval, there is convincing evidence that that proposed value is incorrect.
TRUE
FALSE
A local pizza shop claims that they deliver pizzas in 30 minutes or less. The 95% confidence interval obtained from a random sample of 12 deliveries is [26.8,41.0].
Calculate the point estimate used to create this interval.
7.1 minutes
13.4 minutes
33.9 minutes
30.7 minutes
A local pizza shop claims that they deliver pizzas in 30 minutes or less. The 95% confidence interval obtained from a random sample of 12 deliveries is [26.8,41.0].
Calculate the margin of error used to create this interval.
7.1 minutes
13.4 minutes
33.9 minutes
30.7 minutes
A local pizza shop claims that they deliver pizzas in 30 minutes or less. The 95% confidence interval obtained from a random sample of 12 deliveries is [26.8,41.0].
Is there evidence to suggest that the stated mean delivery time is 30 minutes or less is incorrect?
No. There are values in the interval that are 30 or less, so it is plausible the the pizza shop is making a valid claim.
Yes. There are values higher than 30 in the interval which means that the pizza shop is delivering pizzas in more time than 30 minutes.
No. The interval does not contain 30, so this value must be incorrect.
A magazine reported that 66% of dog owners greet their dog before their spouse of children when they arrive home.
A random sample of 40 dog owners was obtained and a 95% confidence interval was calculated as [0.68, 0.78].
Calculate the point estimate that was used to create this interval
78%
5%
73%
66%
A magazine reported that 66% of dog owners greet their dog before their spouse of children when they arrive home.
A random sample of 40 dog owners was obtained and a 95% confidence interval was calculated as [0.68, 0.78].
Calculate the margin of error that was used to create this interval
78%
5%
73%
66%
A magazine reported that 66% of dog owners greet their dog before their spouse of children when they arrive home.
A random sample of 40 dog owners was obtained and a 95% confidence interval was calculated as [0.68, 0.78].
Is there evidence to suggest that true proportion of dog owner who greet their dog first is not 66%?
No, It is plausible that 66% is correct since it is in the interval.
Yes. Since 66% is not a plausible value of the population parameter, there is evidence that the magazine is incorrect.
I can't tell whether or not 66% is incorrect with any certainty.
Harry is running for town council. He wants to estimate the likelihood of winning. A random sample of registered voters was asked if they planned on voting for Harry. The 95% confidence interval is [0.32, 0.38]
What is the point estimate that was used to create this interval?
0.70
0.35
0.03
0.65
Harry is running for town council. He wants to estimate the likelihood of winning. A random sample of registered voters was asked if they planned on voting for Harry. The 95% confidence interval is [0.32, 0.38]
What is the margin of error that was used to create this interval?
0.70
0.35
0.03
0.65
Harry is running for town council. He wants to estimate the likelihood of winning. A random sample of registered voters was asked if they planned on voting for Harry. The 95% confidence interval is [0.32, 0.38]
How confident should Harry be about his chances of winning?
Better luck next time Harry. It is not plausible that the majority of voters are going to vote for you.
Excellent Harry! It is almost certain that you will win!
