Answer: 31
Step-by-step explanation:
Formula to find the sample size is given by :_
[tex]n=(\dfrac{z^*\cdot \sigma}{E})^2[/tex]
, where z*= critical value corresponds to confidence level.
[tex]\sigma[/tex] = population standard deviation.
E= Margin of error.
As per given , we have
[tex]\sigma=2.8[/tex]
E=1
We know that critical value corresponding to 95% confidence level = z*=1.96
Then, the required sample size would be :
[tex]n=(\dfrac{(1.96)\cdot (2.8)}{1})^2[/tex]
[tex]n=(5.488)^2[/tex]
[tex]n=30.118144\approx31[/tex]
Hence, the required minimum sample size = 31
The sample size has to be 31 for it to be 95% confident and true mean differing from the sample mean by no more than 1 day.
This is the act of choosing the number of observations to be included in a statistical sample.
Sample size (n) = (z* × б / E)²
where z*= critical value corresponds to confidence level , б = population standard deviation and E is margin of error.
= (1.96 × 2.8 /1 )²
= (5.488)²
= approximately 31.
Read more about Sample size here https://brainly.com/question/14470673
