The mean life expectancy of a certain type of light bulb is 945 hours with a standard deviation of 21 hours. What is the approximate standard deviation of the sampling distribution of the mean for all samples with n=50?

To find the approximate standard deviation of the sampling distribution of the mean for all samples with a sample size of n = 50, we can use the formula:

Standard Deviation of the Sampling Distribution of the Mean (Οƒπ‘₯Μ„) = Standard Deviation of the Population (Οƒ) / √(Sample Size)

Given:
Standard Deviation of the Population (Οƒ) = 21 hours
Sample Size (n) = 50

Plugging the values into the formula:

Οƒπ‘₯Μ„ = 21 / √50

Now, let's calculate the approximate standard deviation of the sampling distribution of the mean:

Οƒπ‘₯Μ„ = 21 / √50

Using a calculator or simplifying further:

Οƒπ‘₯Μ„ β‰ˆ 2.97

Therefore, the approximate standard deviation of the sampling distribution of the mean for all samples with a sample size of n = 50 is approximately 2.97 hours.

SEm = SD/√n