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Stats assignment mcq




Question;Question 1 Given a sample with 5;scores: 4, 6, 8, 10, and y, and the mean of this sample is 6, what is the;variance of the sample? (Hint: first find y). Blank 1;Question 2 Given a population;mean weight of 150 pounds and a population standard deviation 40 pounds;express an individual weight of 200 pounds as a z-score. (to two decimal;places, e.g.: 3.21 or 6.00) Blank 1;Question 3 Find the correlation coefficient;for these scores (they are given in the form (x1,y1), (x2,y2) etc): (0,1);(10,3), (4,1), (8,2), (8,3) (express this to 3 decimal places, e.g.:.123 or;-.456) Blank 1;Question 4 Use the least squares;regression equation to find the predicted Y value for an X value of 5, given: r;=.3, SSy=64, SSx=4, mean of y= 30, mean of x= 10 Blank 1;Question 5 You're going skydiving;because you're awesome. The main parachute has to do two things to keep you;alive: release when you pull the cord, (probability of releasing =.9) AND;unfold properly (probability of unfolding =.8). Unfolding is independent of;releasing. OR, if anything goes wrong, your backup parachute will save you;(probability of backup working =.7). The backup parachute only comes into play;if the first parachute fails. What is the probability that you survive, i.e.;that either your primary OR secondary parachute will work? (Hint: this combines;both independent and mutually exclusive events, and the answer will be greater;than.9). Give the answer to three decimal places, e.g.:.999 Blank 1;Question 6 Does eating vegetables;instead of delicious foods affect how long you live? Given a population life;expectancy of 75 years with population standard deviation 5 years, What is the;z-value for a random sample of 25 vegans who live to an average age of 73? Does;this alter life expectancy at a.05 level of significance? Type the z-value in;box 1 to two decimal places (e.g. 3.45), and in box 2 type either yes or no;(yes if this is statistically significant and you reject the null, no if it is;not significant and you fail to reject the null). Blank 1 Blank 2;Question 7 A similar follow-up study;is done on a sample of 25 meat-lovers who never eat vegetables, again randomly;selected from the same general population (population mean life expectancy =;75, population standard deviation = 5). This new sample of meat-eaters live to;an average age of 77. What is the lower limit and upper limit of the 95%;confidence interval for the life expectancy of this sample of meat-lovers? Type;the lower limit in box 1 and the upper limit in box 2, to two decimal places in;each case. Blank 1;Blank 2;Question 8 Is working out every day;BETTER than working out every other day but for twice as long? A random sample;of 42 people are assigned to two groups of equal size: Group 1 works out every;day for one hour, Group 2 works out every other day for two hours, and then;after a month they are tested for how many pushups they can do in one minute.;Group 1 participants do an average of 43 pushups, Group 2 participants do an;average of 32 pushups. Given an estimated standard error of 6 pushups, what is;the t-value? Is the Group 1 workout plan statistically significantly BETTER;than the Group 2 workout plan, at the.05 level? Give the calculated t-value to;two decimal places in box 1, and in box 2 type either yes (if it is statistically;significant and you reject the null) or no if it is not significant. Blank 1;Blank 2;Question 9 Does study group size affect;test performance? From a large class of students, 12 are selected to study for;a test either all alone, with a partner, or with a group of other students. The;four students who studied alone scored: 7, 10, 9, and 6, the four students who;studied with a partner scored: 8, 8, 9, and 7, and the four students who;studied in groups scored: 7, 6, 4, and 3. What is the F-value for this study;(type in box 1 to two decimal places), and is there a statistically significant;effect of study group size on test performance at the.05 level, based on this;data (type yes or no in box 2)? Blank 1 Blank 2 box 2)? Blank 1 Blank 2;Question 10 Do blondes have more fun?;Walking around downtown saturday night, you ask people whether they had a;boring time, a good time, or a great time that night, and note their hair;color. Out of 80 blondes: 20 had a boring night, 20 had a good night, and 40 had;a great night. out of 120 non-blondes: 30 had a boring night, 40 had a good;night, and 50 had a great night. What is the chi-square value for this data;(type in box 1 to two decimal places) and is there statistically significant;relationship between hair color and fun at the.05 level (type yes or no in box;2)? Blank 1 Blank 2


Paper#62400 | Written in 18-Jul-2015

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