# Exam Review

18 Questions  I  By Manello

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 1 The 10% annual death rate of elm trees in one region prompted a research effort intended to prevent future deaths of those trees.  When one treatment was applied to 200 trees, it was observed that 16 of the trees died the following year.  Use a 0.05 disnificance level to test the claim that the proportion of tree deaths for treated trees is less than the 10% rate for untreated trees.  p. 371
 2 A marine biologist obtained weights of salmon caught in Junea, Alaska.  The last digits of those weights were found to have frequencies of 20, 18, 19, 17, 21, 22, 14, 18, 20, 21.  Test the claim that the digits do not occur with the same frequency.  Based on the results what can we conclude about the procedure used to obtain the weights.  p. 501
 3 The beanstalk club is limited to women and men who are very tall.  The minimum hiehg requirement for women is 70 in.  Women's heights have a mean of 63.6 in. and a standard deviation of 2.5 in.  Find the z score corresponding to a womanwith a height of 70 in. and determine whether that height is unusual (p 75).
 4 Among companies doing highway or bridge construction, 80% test employees for substance abuse.  A study involves the random selection of 10 such companies.a) Find the probability that 5 of the 10 companies test for substance abuse.b) Find the probability that at least half of the companies test for substance abuse.c) for such groups of 10 companies, find the mean and standard deviation for the number ( among 10) that test for substance abuse.d) Would it be unusual to find that 6 of 10 companies test for substance abuse? Why or why not?p. 187
 5 According to date from the American Medical Association, 10% of us are left handed.a) If three people are randomly selected, find the probability that they are all left handed.b) If three people are randomly selected, find the probability that at least one of them is left handed.c) If groups of 50 people are randomly selected what is the mean number of left handed poeple in these groups?d) If groups of 50 people are randomly selected what is the mean number of left handed people in such groups?e) Would it be unusual to get 8 left handed people in a randomly selected group of 50 people?  Why or why not?p.251
 6 On a clinical trial of Lipitor, a common drug used to lower chlosterol, one group of patients was given a treatment of 10mg atrovastatin tablets.  That group consists of 19 patients who experienced flu eymptoms and 844 patients who did not.  a) Estimate the probability that a patient taking the drug will experience flu symptoms.b) Is it "unusual" for a patient taking the drug to experience flu symptoms?p. 100
 7 If a couple plans to have five children, what is the probability that they will have at least one girl?  If the couple eventually has 12 children and they are all boys, what can the couple conclude?p. 125
8.  Listed below are the numbers of chirps in 1 min and the corresponding temp indegrees Fahrenheit.a) Is there sufficent evidence to conclude that there is an associated between the number of chirps in a minute and the temperature?b) Find the equation of the straight line that best fits the sample data.c) If a cricket chirps 1234 times in 1 min, what is the best predicted value for the temperature?d) What percentage of the variation in temeprature can be explained by the variation in the cricket chirp rate?e) Can the correlation/regression results be used to show that changes in temperature can cause changes in the cricket chirp rate?p.483
 Chirps in one Min 882 1188 1104 864 1200 1032 960 900 Temperature 69.7 93.3 84.3 76.3 88.6 82.6 71.6 79.6
9.  Using a 0.05 sig level, test the claim that smoking is independent of the education level.  What do you conclude about  the relationship between smoking and education in China?p. 517 @font-face { font-family: "Cambria"; }p.MsoNormal,li.MsoNormal,div.MsoNormal{margin:0cm 0cm 10pt;font-size:12pt;font-family:"Times New Roman";}div.Section1{page:Section1;}
 Primary School Middle School college Smoker 606 1234 100 Never Smoked 205 505 137
 10 The initial test will be conducted by treating six people chosen from a pool of 15 volunteers.  If the treatment group is randomly selected, what is the probability that it consists of the six youngest people in the pool?  If the six youngest are selected, is there sufficient evidence to conclude that instead of being random, the selection was based on age?p. 148
 11 There are eight outcomes that are possible when a couple has three children.  Find the probability of each event:a) Among three children, there is exactly one girl.b) Among three children there are exactly two girls.c) Among three children all are girls.p. 99
 12 A genetics expert has determined that for certain couple, there is a 0.25 probability that any child will have an X-linked recessive disorder.a) Find the probability that among 200 such children, at least 65 of the children have the X-linked disorder.b) A subsequent study of 200 actual births reveals that 65 of the children hav the X linked disorder.  Based on these sample results, construct a 95% confidence interval for the proportion of all such children having the disorder.c) Does it appear that the expert's determination of a 0.25 probability is correct?p. 311
 13 The weights of newborn American babies are normally distributed with a mean of 3420g and a standard deviation of 495g.a) If a newborn baby is randomly selected, find the probability that his or her weight is greater than 300 g.b) If 5 newborn American babies are randomly selected, find the probability that all five have weights greater than 300g.c) If five babies are randomly selected,find the probability that their mean is above 3000g.d) Find P 90 the score separating the botom 90% from the top 10%.p. 373
 14 A biology professor gives a surprise quiz consisting of 10 true/false questions, and she states that passing requires at least 7 correct responses.  Assume that an unprepared student adopts the questionable strategy of guessing for each answer.a) Find the probability that the first 7 responses are correct and the last 3 are wrong.b) Is the probability from part a) equal to the probability of passing?  Why or why not?p. 117
 15 A batch of pills consists of 7 that are good and 3 that are defective.  Three pills are randomly selected and tested.a) How many different samples of pills are possible when three pills are randomly selected (without replacement) from the 10 that are available?b) Find the probability that all three of the defective pills are selected.p. 148
 16 Refer to the given data for the measured amounts of CO from samples of filtered and non filtered king-size cigarettes.  All measurements are in milligrams, and the data are from the Federal.  Use a 0.05 significance level to test the claim that the mean amount of CO in filtered king-size cigarettes is equal to the mean amount of CO for non filtered king size cigarettes.  Based on this result, are cigarette filters effective in reducing CO?Filtered:  14 12 14 16 15 2 14 16 11 13 13 12 13 12 13 14 14 14 9 17 12 Non Filtered: 14 15 17 17 16 16 14 16 p. 422
 17 A) If a couple plans to have 8 children, how many different gender sequences are possible?b) If a couple has four boys, and four girls how many different gender sequences are possible?c) Based on the results, what is the probability that when a couple has 8 children, the result will consist of four boys and four girls?p. 149
 18 A pollster contacts 84 people in the 18-21 age bracket and finds that 73 of them respond and 11 refuse to respond.  When 275 people in the 22-29 age bracket are contacted, 255 respond and 20 refuse.  Assume that 1 of the 359 people is randomly selected.  Find the probability of getting someone in the 18-21 age bracket or someone who refused to respond.  p. 109
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