Question

QUESTION 22 4 points S The lifetime of a particular type of battery is normally distributed with a mean of 1,100 days and a standard deviation of 80 days. The manufacturer randomly selects 400 batteries of this type and ships them to K-Mart. What is the probability the average lifetime of these 400 batteries is between 1,097 and 1,104 days? 4 points s QUESTION 23 Graduate students applying for entrance to many universities must take a Miller Analogies Test. It is known the test scores have a mean of 75 and a variance of 16. In 1990, one hundred students applied for entrance into graduate school in physics. Find the probability that the average score of this group of students is higher than 76,

Answer 1

olan Solution: meanca) - 1100 Sinco):8 na Hon P[1og7 & 8x1104 using een hul limit theorm 2=X-M NNoooo) ost "1097-4 8-M 1104-4 Elun loin olin 1104-1100 :P[1097 > { plot *- 1097-1106. (2x 2/5500 80/3000 P[-0.75<2<L: ] |- PL2-0 0.75] -PC2240] 11- P[2/0.75] - P[2/10] Due to .1-0.22663 -0.15866 symmety - 0.6147 P[1097({ 1104] = 0.6147 Hence the probability

23 Meanim]:75 Versiune erou) - 16 5.0 (o)=4 no100 Pcm76) 3-4 olin 76-75 76-4 > 011n - P[2) w/5100 =PLZ ) 2.5] 0.00 62097 PCT 1757-0.0062097 Hence the probabiling Thank you!