Question

Winter 2018 AT 103 Test II Chapters 6-11 a( \ 1. The average number of miles that 90 truckers drove in a day was 540 with a standard what is the 99% confidence interval of the true mean number of deviation of 40 miles, miles driven by all truckers? Dr. Christina Cuttleman, a nutritionist, claims that the average number ofcalories in a serving of popcorn is 75 with a standard deviation of 7. A sample of 50 servings of popcorn yields an average of 78 calories. Check Dr. Cuttleman's claim at 2. It has been claimed that at UC.LA, at least 40% of the students live on campus. From a sample of 250 students, 90 live on campus. Does the evidence support this claim at 3. cx 001 ? 4. Joan moves into her new apartment and wants to purchase a new couch. She wants to determine ifthere is any difference between the average costs of couches at two different stores. Test the hypothesis that there is no difference at -0.05. Assume the populationofcouches is normally distributed. Store 1 Store 2 x $650 $730 $78 21 n 24 A researcher wishes to determine ifthere is a relationship between the sex of an individual and the amount of coffee consumed. The following data was obtained for the number of cups of coffee consumed. Are the sex of the drinker and the amount of coffee independent 5. events ? Use 0os Low Medium High 13 Males 25 12 Females 6. An anatomy teacher hypothesizes that the final grades in her class are distributed as 10% A's, 23% B's, 45% C's, 14% D's, and 8% F's. If at the end ofthe semester she has the following grades was she correct in her hypothesis? Use (-00l hubls A BCDF 6 14 22 8 4 A quality control expert wants to estimate the proportion of defective components that are being manufactured by his company to within 2.5%. A sample of 300 components showed that 20 were defective. How large a sample is needed to estimate the true proportion of defective components with 99% confidence? 7. Mrs. Smith's reading class can read an average of 175 words per minute with a standard deviation of 20 words per minute. The What is the minimum number of words per minute a student would have to read in order to get the award? 8. top 3% of the class is to receive a special award

Answer 1

he, X=540,6 40, n-90 ugging in ts values, ne get our conkidme intaval oa 529.12, 550.89 g Pap Wewill reieck-our 50 test statistic Hence ,we rejechtha null kỜpotheas erejedh aum One-tauled 0-01 0.4(+ o -1.22-〈-1% 一100x 0.1 e-we have tD accept ourt null hardheais the evidone dves no pnt Ha jiven claim

α=0.05. Ount-statishic is given by 650 730 -3.79 612 782 21 2) (ISS.0y+ 289.71) 2 A'38 n2-1 2 3 20 → Reject null hVpolheas 0. 0006