Answer :
Explanation:
Since we have given that
n(U) = 120, where U denotes universal set ,
n(F) = 45, where F denotes who speak French,
n(S) = 42 , where S denotes who speak Spanish,
n(F∪S)' = 50
n(F∪S) = n(U)-n(F∪S) = 120-50 = 70
Now, we know the formula, i.e.
n(F∪s) = n(F)+n(S)-n(F∩S)
⇒ 70 = 45+42-n(F∩S)
⇒ 70 = 87- n(F∩S)
⇒ 70-87 = -n(F∩S)
⇒ -17 = -n( F∩S)
⇒ 17 = n(F∩S)
Answer:
The 90% confidence interval for the population mean iron concentration is between 0.167 cc/m³ and 0.195 cc/m³.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 0.181 - 0.0140 = 0.167 cc/m³.
The upper end of the interval is the sample mean added to M. So it is 0.181 + 0.0140 = 0.195 cc/m³.
The 90% confidence interval for the population mean iron concentration is between 0.167 cc/m³ and 0.195 cc/m³.