STATISTICS FINAL EXAM.docx

# STATISTICS FINAL EXAM.docx - StaTsTcs SU/17 – Chapters...

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Statistics SU/17 – Chapters 1-14 ___ 1. The mean weight of loads of rock is 47.0 tons with a standard deviation of 6.0 tons. If 9 loads are chosen at random for a weight check, find the probability that the mean weight of those loads is less than 46.0 tons. Assume that the variable is normally distributed. A) 18.44 B) 30.85 C) 69.15 D) 81.56 ___ 2. Compute the value of the correlation coefficient. 48 52 45 59 56 94 91 86 101 101 x y ___ 3. An educational researcher is analyzing the test scores for physics students taught using two different methods - a traditional method, and a web-based self-paced method. Can he conclude, at α = .05, that the test scores in the web-based self-paced method are lower? Traditional Web-based Self-paced Sample size 60 70 Mean test score 84 81 Population variance 26 42 ___ 4. A running coach wanted to see whether runners ran faster after eating spaghetti the night before. A group of six runners was randomly chosen for this study. Each ran a 5 kilometer race after having a normal dinner the night before, and then a week later, reran the same race after having a spaghetti dinner the night before. The times for their races are shown in the table below. What test value should be used in a t test for these dependent samples? Runner 1 Runner 2 Runner 3 Runner 4 Runner 5 Runner 6 Regular Dinner 981 s 966 s 990 s 951 s 997 s 977 s Spaghetti Dinner 972 s 959 s 985 s 948 s 996 s 978 s ___ 5. In a large bag of marbles, 40% of them are red. A child chooses 4 marbles from this bag. If the child chooses the marbles at random, what is the chance that the child gets exactly three red marbles? A) 0.154 B) 0.230 C) 0.346 D) 0.256 Page 1

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___ 6. A recent statistics exam yielded the following 10 scores. Construct a frequency polygon distribution using the class limits shown below. 81, 99, 77, 67, 93, 70, 76, 86, 79, 71 Class Limits Midpoints Tally Frequency 61-70 71-80 81-90 91-100 Page 2
___ 7. A random group of students was asked to name their favorite type of music. The campus radio station believes that 18% of the students prefer rap, 22% prefer rock, 15% prefer country, 17% prefer new age, and 28% prefer oldies. Is there evidence to reject this hypothesis at α = 0.05? Type of music Rap Rock Country New Age Oldies Number of Students 21 25 19 18 16 A) There is evidence to reject the claim that the favorite music types are distributed as claimed because the test value 9.488 > 7.240 B) There is not evidence to reject the claim that the favorite music types are distributed as claimed because the test value 7.240 < 7.815 C) There is evidence to reject the claim that the favorite music types are distributed as claimed because the test value 11.07 > 7.240 D) There is not evidence to reject the claim that the favorite music types are distributed as claimed because the test value 7.240 < 9.488

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