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Unformatted text preview: Sim 1 39 Name Quiz 5A Rec: id: g Use the following information for problems 12
Thirteen percent of people are left—handed. A {aséom sample of 12 persons is selected. 1. (2 points) How many left handed people do you expect to ﬁnd in tho sample of 32 EJQESOEIS?
‘E 1 4%
ﬂgwﬂ§w§25 35;; 2. (2 poims) Find the probability [has at least two of the .112. gorsoss is left—handed.
WW 3:} s: M ﬁgs o a W Wag
xiv g” E i;€g{‘§§f “E” iésgiglﬁ; “? 3 : ﬁ‘ “WE
ago. £9. 2%?s % '32?st
Answer ‘ g M
2:. 2w ,Sssss lasss3
3. (i goént) Which of the following is NOT a property of the binomial distribution?
A. There are a fixeé number {n} of obsesvstions.
@ The probability of success and this probability of failure must be equal. C. The observations or trials are inéependont.
D. For each trial only two, mumally oxclusivo outcomes are possible. Answer U52 the following information to answer Questions 45 ?W 3?: Ai a large computer company, 88% of all employees have a college degree. Soppose a random
sample of 4‘10 smployeos is obtained and 85% of them have a 50116sz degree.
{3 7.; ago § :2 u 3 §
4” (2 points) What are the mean and standard omission of the sample pion? giivs’é :2 o 5&9 a :_ ' WW
Answer: Mean: Standard Deviatioo We? eeéee 6. (3 points) Suppose that 15% of all Americans use CNN as {heir 'prih'iaiy source of news.
A random sample of 3.90 Americans is selected. What is the probability {hat between 10
mod 22 peopie in year sample of 180 Americans will use CNN as their primary news source? ?€ Answer r éﬁé {‘  ‘ ‘gl‘ig” ﬁg“ We ee 4. Use the foiiowing to answor grohiems 7~10
For the popuiatioo of farm workers in New Zealand, the weekiy income has a distribution that is skewed to the right with a mean of $530 and e stendarci deviation of $160. A researcher decides to take a random sample of 229 workers.
7’. (2 points) Describe the sampiing ciistribution of the sarnpie mean for the 120 workers. W W “3.
X W m toe; z: or: we is
3. {3 points) Find the probabiiity that the met weekly income earned by the :20 workers
exceeds $64500. ? {9 ﬁﬁg x? % g :3 WE a? gagﬁgf‘)
2: We lithe; z: ? er? iii$3
Answer. g 8% {a .$G§§ x 9. (2 points) What is the mean weekly income for the sampie of 120 workers such that the
percentage above this level is 7%? r e: to? ' J 10. (1 point) Suppose that a sampie of 1200 households had been seiected. instead of 120,
Which of the following statements is correct?
A. The variability of the sample mean wouid he increased, because it is larger.
B. The variabiiity of the sampie mean would be enchaeged; it does not depend or: n.
The variabiiity of the sample mean would be decreased. became n is larger.
. There is not sufficient information given to know how the variabiiity of the
samgle mean would be affected. R $ % Answer: Efﬁe ...
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 Spring '07
 Helen
 Statistics

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