Question

For population parameter μ = true average resonance frequency for all tennis rackets of a certain type, each of these is a confidence interval. (114.4, 115.6) and (114.1, 115.9) What is the value of the sample mean resonance frequency?

a. 114.5
b. 115.8
c. 114.1
d. 115.0

Answer 1

X[bar]= 115

Explanation:

Hello!

Every Confidence interval to estimate the population mean are constructed following the structure:

"Estimator" ± margin of error"

Wich means that the intervals are centered around the sample mean. To know the value of the sample mean you have to make the following calculation:

`X[bar]= (Upper bond + Low bond)/(2)`

`X[bar]= (115.6+114.4)/(2)` = 115

Since both intervals were calculated with the information of the same sample, you can choose either to calculate the sample mean.

I hope it helps!