the length of a spool of ribbon with a z-score of 0.7 is 92.3 cm
Explanation:
Here we have , The lengths of spools of ribbon are normally distributed with a mean of 91.4 centimeters and a standard deviation of 1.3 centimeters. What is the length of a spool of ribbon with a z-score of 0.7 . Let's find out:
According to Question we have following parameters as :
X = the length of a spool of ribbon
Mean(x) = 91.4 cm
standard deviation(y) = 1.3 cm
Z = 0.7
We know that Z score is given by :
⇒

⇒

⇒

⇒

Therefore , the length of a spool of ribbon with a z-score of 0.7 is 92.3 cm