Answer:
213 samples needed for 99% confidence interval
Step-by-step explanation:
We know that:
minimum size of sample needed to be sure about total measurement less than 3.5 degree is given as
[tex]n = [\frac{z_{\alpha/2}\times s}{E}]^2[/tex]
where,
s is standard deviation = 19.8 degree
E IS MARGIN OF ERROR = 3.5 degree
[tex]z _{\frac{\alpha}{2}}[/tex] right tail critical value of
Z [tex]z _{\frac{\alpha}{2}} = z _{\frac{0.01}{2}} = z_{0.005} = 2.58[/tex]
so, minimum size of sample needed is
[tex]n = [\frac{2.58\times 19.8}{3.5}]^2[/tex]
n = 213.02
Therefor 213 samples needed for 99% confidence interval
