Question

An experiment to investigate the survival time in hours of an electronic component consists of placing the parts in a test cell and running them under elevated temperature conditions. Six samples were tested with the following resulting failure times (in hours): 34, 40, 46, 49, 61, 64. (a)Calculate the sample mean and sample standard deviation of the failure time.

Answer 1

The sample mean of failure time was of 49 hours.

The standard deviation of the failure time was of 11.7 hours.

Explanation:

Sample mean:

Sum of all values divided by the number of values. So

`\overline{x} = (34+40+46+49+61+64)/(6) = 49`

The sample mean of failure time was of 49 hours.

Standard deviation:

Square root of the division between the sum of the differences squared betweene each value and the mean, divided by the sample size subtracted by 1. So

`s = \sqrt{((34-49)^2+(40-49)^2+(46-49)^2+(49-49)^2+(61-49)^2+(64-49)^2)/(5)} = 11.7`

The standard deviation of the failure time was of 11.7 hours.