A normal population has the mean of 10 and the variance of 25 . A random sample of size n-28 is selected. (a) Find the standard deviation of the sample mean. Round your answer to two decimal places (e. g. 98.76)
(b) How large must the sample be if you want to halve the standard deviation of the sample mean?

Step-by-step explanation:

Given that:

population mean = 10

variance = 25  ; = = 5

sample size n = 28

The standard deviation of the sample mean:

=

= 0.95

To halve the standard deviation of the sample mean, the size of how large the sample will be can be computed as follows:

= 2

n = 4 × 28

n = 112

exa:

)

3+11

14

step-by-step explanation:

from this example, we can see that subtracting with integers is the same as adding the opposite. we can solve using a number line or by using the saying "keep, change, change" to us solve. it is important to remember that we can subtract a negative and end up with a larger number than we started with.