Respuesta :
The following are basic points
Explanation:
a) The Group R have no experience, hence they need more time to complete
the Histogram II is appropriate for them as more data is to the right, where more time is taken
b) if we combine it will be something like below
c) n = 70 > 30 , hence bythe central limit theorem
The standrad normal distribution formula is used, mu is taken as 70 and whereas standard deviation is 26.5 as given in the question.
A distribution may or may not follow a standard normal distribution.
The sampling distribution of the sample mean is standard normal distribution.
The given parameters are:
- The population mean [tex]\mu = 70[/tex]
- The standard deviation [tex]\sigma = 26.5[/tex]
- The sample size, [tex]n = 50[/tex].
The population mean (70) is greater than 30.
So, we can make use of the central limit theorem.
Using the central limit theorem, we calculate the z-score using the following formula:
[tex]z= \frac{\bar x - \mu}{\sigma /\sqrt{n}}[/tex]
So, we have:
[tex]z= \frac{\bar x - 70}{26.5/\sqrt{50}}[/tex]
[tex]z= \frac{\bar x - 70}{26.5/7.1}[/tex]
This gives
[tex]z= \frac{\bar x - 70}{3.7}[/tex]
For whatever value, the sample mean has, the sampling distribution of the sample mean is standard normal distribution.
Read more about sampling distribution at:
https://brainly.com/question/12892403