Answer:
(a) [tex]\mu=25\ \text{minutes}[/tex]
(b) [tex]\sigma=13\ \text{minutes}[/tex]
(c) [tex]n=20[/tex].
(d) [tex]\mu_{\bar x}=\mu=25\ \text{minutes}[/tex]
Step-by-step explanation:
Let the random variable X represent the time it takes a certain brand of ibuprofen to start working.
(a)
The mean time it takes a certain brand of ibuprofen to start working is, 25 minutes.
That is, [tex]\mu=25\ \text{minutes}[/tex].
(b)
The standard deviation of time it takes a certain brand of ibuprofen to start working is, 13 minutes.
That is, [tex]\sigma=13\ \text{minutes}[/tex].
(c)
The sample selected by a pharmacist is of size, 20.
That is, [tex]n=20[/tex].
(d)
The mean of the sample means is:
[tex]\mu_{\bar x}=\mu=25\ \text{minutes}[/tex]
