6.
2 answers:
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Answer:
Sample size= 956
Step-by-step explanation:
Hello!
You need to construct an 80% CI for the average life of batteries. (hours)
The study variable is:
X: Lifespan of a battery.
X~N(μ; σ²)
The population standard devition isσ= 8
The interval to estimate the population mean follows the structure:
"Point estimator" ± "margin of error"
X[bar] ± * (σ/√n)
X[bar] is the sample mean
* (σ/√n) is the margin of error of the interval (d)
Using the margin of error you can calculate the sample size:
d= * (σ/√n)
n= (σ* )²
n=
n= 955.77 ≅ 956
I hope it helps!