##### Asked by: Irania Rutenkroger
asked in category: General Last Updated: 15th March, 2020

# What does 80% confidence mean in a 80% confidence interval?

A 80% confidence interval means : "You are confident at 80% that the real value is in the interval". In order to get a higher level of confidence, you have to take a wider interval.

Besides, what is the 80% confidence interval?

Statistics For Dummies, 2nd Edition

Confidence Level z*– value
80% 1.28
85% 1.44
90% 1.64
95% 1.96

Also, how do you find 80 confidence interval? Because you want a 95% confidence interval, your z*-value is 1.96. (The lower end of the interval is 7.5 – 0.45 = 7.05 inches; the upper end is 7.5 + 0.45 = 7.95 inches.)

Statistics For Dummies, 2nd Edition.

Confidence Level z*-value
80% 1.28
90% 1.645 (by convention)
95% 1.96
98% 2.33

Also asked, what does a 95% confidence interval mean?

The 95% confidence interval defines a range of values that you can be 95% certain contains the population mean. With large samples, you know that mean with much more precision than you do with a small sample, so the confidence interval is quite narrow when computed from a large sample.

Why is 80 confidence interval narrower than 95?

Apparently a narrow confidence interval implies that there is a smaller chance of obtaining an observation within that interval, therefore, our accuracy is higher. Also a 95% confidence interval is narrower than a 99% confidence interval which is wider. The 99% confidence interval is more accurate than the 95%.

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