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Stats132A- Ch.1-4 Test Review

Terms in this set (21)

Identify the type of sampling used​ (random, systematic,​ convenience, stratified, or cluster​ sampling) in the situation described below.
A man is selected by a marketing company to participate in a paid focus group. The company says that the man was selected because he was randomly chosen from all adults. nothing nothing nothing nothing
Which type of sampling did the marketing company​ use?
Random Sampling
etermine whether the given description corresponds to an observational study or an experiment.
In a study of 403 men with a particular​ disease, the subjects were injected with vitamins to determine if the vitamins have an effect on the disease.
Does the given description correspond to an observational study or an​ experiment?
The given description corresponds to an experiment.
Identify which type of sampling is​ used: random,​ systematic, convenience,​ stratified, or cluster.
To determine customer opinion of their pricing​, Home Depot randomly selects 80 check out lines during a certain week and surveys all customers in the check out lines.
Which type of sampling is​ used?
Cluster
Testing for a disease can be made more efficient by combining samples. If the samples from three people are combined and the mixture tests​ negative, then all three samples are negative. On the other​ hand, one positive sample will always test​ positive, no matter how many negative samples it is mixed with. Assuming the probability of a single sample testing positive is 0.1​, find the probability of a positive result for three samples combined into one mixture. Is the probability low enough so that further testing of the individual samples is rarely​ necessary?
The probability of a positive test result is
. 271.
​(Round to three decimal places as​ needed.)
Is the probability low enough so that further testing of the individual samples is rarely​ necessary? The probability is not​ low, so further testing of the individual samples will not be a rarely necessary event.
When testing for current in a cable with six ​color-coded wires, the author used a meter to test four wires at a time. How many different tests are required for every possible pairing of four ​wires?
15
In a computer instant messaging​ survey, respondents were asked to choose the most fun way to​ flirt, and it found that ​P(D)equals0.820​, where D is directly in person. If someone is randomly​ selected, what does Upper P left parenthesis Upper D overbar right parenthesis ​represent, and what is its​ value?
is the probability of randomly selecting someone who does not choose a direct​ in-person encounter as the most fun way to flirt.
Upper P left parenthesis Upper D overbar right parenthesisequals
. 18 ​(Simplify your​ answer.)
Identify which type of sampling is​ used: random,​ systematic, convenience,​ stratified, or cluster.
Upper A television station asks its viewers to call in their opinion regarding the desirability of programs in high definition TV.
Which type of sampling is​ used?
Convenience
If your score on your next statistics test is converted to a z​ score, which of these z scores would you​ prefer: minus​2.00, minus​1.00, ​0, 1.00,​ 2.00? Why?
The z score of 2.00 is most preferable because it is 2.00 standard deviations above the mean and would correspond to the highest of the five different possible test scores.
Winning the jackpot in a particular lottery requires that you select the correct four numbers between 1 and 62 ​and, in a separate​ drawing, you must also select the correct single number between 1 and 38. Find the probability of winning the jackpot.
The probability of winning the jackpot is
StartFraction 1 Over 21,198,110 EndFraction
.
Determine which of the four levels of measurement​ (nominal, ordinal,​ interval, ratio) is most appropriate for the data below.
Years in which a war was started
The interval level of measurement is most appropriate because the data can be ordered comma differences can be found and are meaningful comma and there is no natural starting zero point.
For a certain instant lottery game comma the odds in favor of a win are given as 1 to 99. Express the indicated degree of likelihood as a probability value between 0 and 1 inclusive.
The probability is
. 01.​(Round to two decimal places as​ needed.)
Determine whether the value is from a discrete or continuous data set.
Population of a city is 39 comma 450
Discrete
A polling company reported that 47​% of 2302 surveyed adults said that they play basketball. Complete parts​ (a) through​ (d) below.
a. What is the exact value that is 47​% of 2302​?
The exact value is
1081.94.
​(Type an integer or a​ decimal.)
b. Could the result from part​ (a) be the actual number of adults who said that they play basketball question mark Why or why​ not?
What could be the actual number of adults who said that they play basketball question mark
No, the result from part​ (a) could not be the actual number of adults who said that they play basketball because a count of people must result in a whole number.
The actual number of adults who play basketball could be
1082. ​(Type an integer or a​ decimal.)
Among the 2302 ​respondents, 926 said that they only play hockey. What percentage of respondents said that they only play​ hockey?
​40.23%
​(Round to two decimal places as​ needed.)
The principle of redundancy is used when system reliability is improved through redundant or backup components. Assume that a​ student's alarm clock has a 10.7​% daily failure rate.
What is the probability that the​ student's alarm clock will not work on the morning of an important final​ exam?
.107
The principle of redundancy is used when system reliability is improved through redundant or backup components. Assume that a​ student's alarm clock has a 10.7​% daily failure rate.
If the student has two such alarm​ clocks, what is the probability that they both fail on the morning of an important final​ exam?
.01145
The principle of redundancy is used when system reliability is improved through redundant or backup components. Assume that a​ student's alarm clock has a 10.7​% daily failure rate.
What is the probability of not being awakened if the student uses three independent alarm​ clocks?
.00123
The principle of redundancy is used when system reliability is improved through redundant or backup components. Assume that a​ student's alarm clock has a 10.7​% daily failure rate.
Do the second and third alarm clocks result in greatly improved​ reliability?
Yes, because total malfunction would not be​ impossible, but it would be unlikely.
You are certain to get a queen when selecting 49 cards from a shuffled deck. Express the indicated degree of likelihood as a probability value between 0 and 1 inclusive.
The probability is
1.
​(Type an integer or a​ decimal.)
Several studies showed that after regular exercise on a treadmill​, subjects had lowered blood pressure. High blood pressure has been associated with increased risk of heart disease and stroke. A fitness equipment company financed this research. Identify what is wrong.
It is questionable that the sponsor is a fitness equipment company because this sponsor can be greatly affected by the conclusion.
Use the​ F-scale measurements of tornadoes listed in the accompanying table. The range of the data is 5.0. Use the range rule of thumb to estimate the value of the standard deviation. Compare the result to the actual standard deviation of the​ data, 1.2.
The standard deviation is approximately 1.3.
The estimated standard deviation is
within 0.5 of
the actual standard deviation.​ Thus, the estimated standard deviation
is not
substantially different from the actual standard deviation.
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