Respuesta :
Answer:
The sample mean service life for sample 2 is 515 hours.
Step-by-step explanation:
The design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces.
The distribution of service life in control is, normal with parameters,
Mean (μ) = 500 hours
Standard deviation (σ) = 20 hours
The random sample of 4 headlamps from 3 different production batches is:
Sample 1: 495, 500, 505, 500
Sample 2: 525, 515, 505, 515
Sample 3: 470, 480, 460, 470
The sample mean is a statistic, defined as the average value of the data in the sample.
It is computed using the formula:
[tex]\bar X=\frac{1}{n}\sum X_{i}[/tex]
Compute the sample mean service life for sample 2 as follows:
[tex]\bar X=\frac{1}{n}\sum X_{i}[/tex]
  [tex]=\frac{1}{4}\times [525+515+505+515]\\=\frac{2060}{4}\\=515[/tex]
Thus, the sample mean service life for sample 2 is 515 hours.
