Aprevious analysis of paper boxes showed that the standard deviation of the length is 9mm. what is the 98% confidence interval for the average length of a box. how many boxes does he need to measure to be accurate within 3 millimeters.

We cannot calculate the confidence interval without the sample size.  However, for the second question, the sample size needed would be 49.

The formula we use is



To find the z-score:
Convert 98% to a decimal:  0.98
Subtract from 1:  1-0.98 = 0.02
Divide by 2:  0.02/2 = 0.01
Subtract from 1:  1-0.01 = 0.99

Using a z-table (http://www.z-table.com) we see that this value is closest to a z-score of 2.33.

Using the z-score, our standard deviation (9) and our margin of error (3), we have:

Hold on lemme do the work

The answer is 270 cars.you can do this by making a proportional relationship. for instance, 200 is the whole we are using, so on a “number line” 200 would be over 100%. now, since he sells 35% more, add 35% to 100% to get 135% on the other side of the “number line” on the bottom half, leaving the top half empty.cross multiply 200 by 135 then divide by 100 to get your answer. i hope this , if it did, , if you don’t mind, giving me brainiest! 200/100% } 200 • 135 /100 ? /135%