If you are trying to find the unit rate, or amount per pound, you would divide 299 by 14, and add the decimal point where it was. So, 299/14=21.35. After you do the division, move the decimal point 2 places to the left. So, 21.35 with the decimal point 2 places to the left=21 cents. So the unit rate of 2.99 for 14 pounds is 21 cents per pound.
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 the margin of error M
In which is the standard deviation of the population and n is the size of the sample.
How many random IQ scores must be obtained if we want to find the true population mean (with an allowable error of 0.5) and we want 97 percent confidence in the results
We need at least n scores, in which N is found when . So