les after press\" cotton fabrics are treated to improve their recovery from wrin
ID: 3171977 • Letter: L
Question
les after press" cotton fabrics are treated to improve their recovery from wrinkles after washing. Unfortunately, the treatment the also reduces the strength of the fabric. breaking strength of untreated fabric is normally distributed with mean 51 pounds and standard deviation 2.4 pounds. The same type of fabric after treatment has normally distributed breaking strength with mean 17.4 pounds and standard deviation 1.9 pounds. A clothing manufacturer tests 5 specimens of each fabric. All 10 strength measurements are independent. (a) What is the probability that the mean breaking strength of the 5 untreated specimens exceeds 50 pounds? 8251 (b) What is the probability that the mean breaking strength of the 5 untreated specimens is at least 25 pounds greater than the mean strength of the 5 treated specimens?Explanation / Answer
b. 25 greater than mean strength of the 5 treated speciments
so P(x>=25+17.4)=P(x=42.4)=P(z>=42.4-51/2.4)=P(z>=-3.58)=0.9998
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.