Math 112 Exam 1 Name (PRINT) ______Key Spring 2009______Good Luck! 100points total
Show all work for full credit! Box your answers! Round to four decimal places! Write neatly with pencil!
I. Define or explain the meaning of the following: (2 points each)
a) Parameter: See book
b) Sample: See book
c) Statistic: See book
d) Population: See book
e)Standard Deviation: See book
f) Random Sample: See book
II Give a specific example of the following types of data: (2 points each)(Answers may vary)
a) Qualitative Data: Names like, Frank, Jim, Joe, Alex.
b) Quantitative Data: Distance like, height of Mount Everest.
c) Discrete Data: Number of keys on my key chain.
d) Continuous Data: Weights of books
III. Provide the appropriate notation for the following: (2 points each)
a) Symbol for the sample variance________
b) Symbol for the population mean_______
c) Symbol for sample mean_________
d) Symbol for population variance________
e) Symbol for standard deviation of the sample________
f) Symbol for the standard deviation of the population_______
IV. True or False (2 points each)
___T___Two events A and B are dependent if the occurrence of one effects the probability of
the occurrence of the other.
___F___Random Sample is a sample selected in such a way that allows every member of the population to not have the same chance of being chosen.
___F___Mutually Exclusive eventsare independent.
___T___On some occasions the probability of an event can be 1.
___F___The probability of an impossible event is 1.
___T___ If a sample has a variance of 0.25, it’s standard deviation is 0.5.
__F___ The probability of event A or B is smaller than probability of event A and B.
___F____Mutually Exclusive events con occur at the same time.
____F___Mario calculated a probability and got9/8. This is a possible answer in probability.
V.(10points total) Let E and F be two events of an experiment with sample space S. Suppose P(E)=0.4, P(F)=0.7, and P(E∩F)=0.2. Compute:
(a)
(b) Show why P(E and F) are not independent. Hint: Independence rule.
They are not independent because:
VI. The table below describes the smoking habits of a group of asthma sufferers. (10 points total)
Nonsmoker / Occasional Smoker / Regular Smoker / Heavy Smoker / TotalMen / 384 / 33 / 64 / 49 / 530
Women / 349 / 44 / 72 / 38 / 503
Total / 733 / 77 / 136 / 87 / 1033
a)If one of the 1033 people is randomly selected, find the probability that the person is a man or a heavy smoker
b)If one of the 1033 people is randomly selected, find the probability that the person is a man given is a heavy smoker.
VII. (a, b, c, d, f =2pts each; e= 5pts) The Down Jones Industrial Average Yearly Returns are on the right table. Find the following:
a)Find the mean.
b) Find the mode: No Mode
c) Find the median: -0.61
d) Find the range: 58.32%
e) Find the variance:(show formula and plug in numbers from your calculator, than work out the variance)
f) Find the standard deviation.
VIII. (5 points) Use the empirical rule. IQ scores have a bell shape distribution with mean 100 and a standard deviation of 15. Approximately what percentage of IQ scores is between 70 and 130?
Approximately 95 % of the IQ scores are between 70 and 130
IX. (5 points) Scores on an Elementary Statistics test at CerritosCollege have a mean of 73 and a standard deviation of 9. Frank has a score of 73. Convert Frank’s score to a z-score.
X. (5 points) Circle the right answer.
1) The following set of data represents letter grades on a test in a Statistics class:
A,A,A,B,B,B,B,B,C,C,C,C,C,C,C,C,C,CC,D,D,D,D,F.
Select the most appropriate measure of central tendency for the data described
a) Meanb) Medianc) Moded) Midrange
2) The measure most affected by extreme values is:
a) Meanb) Medianc) Moded) Midquartile
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