Answer:
Critical value: 
The 90% confidence interval for the population mean bromide concentration is (0.376, 0.39).
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
. This value of z is the critical value
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 mean subtracted by M. So it is 0.383 - 0.0066 = 0.376 cc/cubic meter
The upper end of the interval is the mean added to M. So it is 0.383 + 0.0066 = 0.39 cc/cubic meter
The 90% confidence interval for the population mean bromide concentration is (0.376, 0.39).
Answer:
215
Step-by-step explanation:
60=50
258=?
258 divided by 60 = 4.3
50 x 4.3 = 215
Answer:

Step-by-step explanation:
Given : 8%
To find the decimal value of the percentage number
Remove the percentage symbol with 100 in the denominator
gives

Now taking the numerator to the decimal place equal to the number of zeros in the denominator or simply divide denominator with numerator.
Gives = 
So, the decimal equivalent of the given value is 
He would only be able to make 6 rows with 3/4 of another
The fraction part of a mixed numeral is added to the whole number.
Use a calculator to divide 13/20.
13/20 = 0.65
34 13/20 = 34 + 13/20 = 34 + 0.65 = 34.65