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Psych 311: Statistics Exam 2
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Terms in this set (79)
The proportion or fraction of times an outcome is likely to occur is referred to as
A. probablity
B. a random event
C. sample space
D. luck
A
A news poll showed that voters had no preference for either of three candidates. In this example, the probability of a vote for, say, Candidate A equals
A. 1/2
B. 1/3
C. 2/3
D 1.00
B
a gambler rolls a 3 with one roll of a single fair die. Given that the die was six-sided, what was the probability of rolling a 3 with one roll?
A. 1/6
B. 3/6
C. 1/9
D. 3/9
A
The following are six random outcomes for a sample space: -1, -3, -3, -2, -5, and -6. What is the probability of selecting a -3 in this example?
A. 1/6
B. 2/6
C. -2/6
D. -3/6
B
Which rule states that when two outcomes are mutually exclusive, the probability that either one of these outcomes will occur is the sum of their individual probabilities?
A. additive rule
B. multiplicative rule
C. both A and B
D. none of the above
A
The probability that someone in the human population has blood type AB is about p=.08; the probability that someone has blood type O is about p=.25. Knowing that each individual can have one and only one blood type, what is the probability that a person has an AB or O blood type?
A. .33
B. .02
C. 1.00
D. this state of affairs is not possible.
A
suppose that the probability that any child of an alcoholic parents becomes alcoholic is p=.16. Assuming independent outcomes, the probability that two children of alcoholic parents will be alcoholic equals
A. .16
B. .32
C. .25
D. .03
D
the distribution of probabilities for each outcome of a random variable that sums to 1.00 is called a
A. random variable
B. probability distribution
C. conditional probability
D. sample space
B
a professor records the grades for his class of students. he finds that the probabiltiy that a student earns an A is p=.14; earns a B is p=.36; earns a C is p=.32; earns a D is p=.10; earns an F is p=.08. What is the probability that a student earns a B or better in this class?
A. .36
B. .14
C. .86
D. .50
D
Each of the following is an example of a binomial distribution, except
A. the number of heads in ten flips of a fair coin
B. the number of males and females in a sample
C. the number of votes for or against a candidate
D. the time it takes to complete a driving test
D
the mean of a probability distribution is called the
A. expected value of the mean
B. mathematical expectation
C. both A and B
D. none of the above
C
the sample space is equal to the total number of random outcomes possible for a random variable
A. true
B. False
A
the probability of an outcome is particularly useful for predicting the likelihood of fixed events
A. true
B. false
B
probability ranges between 0 and 1 and is never negative
A. true
B. false
A
the probablity that a participant is married is p(M) =.60. the probability that a participant is married and "in love" is p(m^L) =.46. Thus, the probability that a participant is in love, given that the participant is married is p=.77
A. true
B. false
A
probability distribution display the probability of each possible outcome for a given random variable
A. true
B. false
A
the expected value of a random variable is the mean of a probability distribution
A. true
B. false
A
While the expected value of the mean estimates the average outcome, the standard deviation of a probability distribution estimates the distance that all other outcomes deviate from the mean
A. True
B. False
A
Binomial probability distribution is constructed for random variables that have at least two possible outcomes
A. True
B. False
B
I theoretical distribution that evenly Distributes data around the mean, median, and mode is called the
A. Normal distribution
B. Bell shaped distribution
C. Gaussian distribution
D. All of the above
D
Most behavior is believed __________ a normal distribution
A. Be exactly equal to
B. Not resemble at all
C. Approximate
C
What is the Z score for scores in the bottom 10%?
A. 1.28
B. 2.32
C. -2.32
D. -1.28
D
Normal distribution, 50% of all the data
A. Fall above the mean
B. Fall below the median
C. Fall above and below the mode
D. All of the above
D
Which of the following is not a step to locate a score of the normal distribution?
A. Locate Z score associated with the given proportion in the unit normal table
B. Transform the score into a raw score (x)
C. Transformer a raw score (x) into a z score
C
In a normal distribution escort it will always be more probable than a score of zero
A. True
B. False
B
For set of data with 25+ or -2.5, at least 95% of scores fall between 20 and 30
A. True
B. False
A
The binomial probability distribution is distributed with u=np and o=/-npq
A. True
B. false
A
A binomial probability distribution is the distribution of random outcomes for a bivariate or dichotomous random variable
A. True
B. False
A
Assume number of days absent is normally distributed. If the sample mean is eight and the standard deviation is two, what is the Z score for a person with two days absent?
A. -3
B. -2
C. 3
D. 99
A
Distribution of all sample means for sample variance is that could be obtained in samples of a given sides from the same population is called
A. Conditional procedure
B. The sampling distribution
C. Sampling without replacement
D. Random sampling
B
A researcher selects from the participant pool for males and six females. He determines that the probability of selecting two males participants is P=.16. Based on this probability what strategy did the researcher use to sample participants
A. Sampling with replacement
B. Sampling without replacement
A
a researcher selects a sample of size 6 from a population of size 10. how many possible samples of this size can be selected using theoretical sampling>
A. 100,000
B. 1,000,000
C.10,000,000
D. over 60,000,000 samples
B
suppose you select a sample of three people from a population of four (A, B, C, D) Which of the following samples is possible using the experimental sampling strategy?
A. persons a, c, and A
B. persons a, d and d
C. persons b, c, and d
D. persons b, a, and b
C
as sample size increases, the standard error of the mean
A. increases
B. decreases
C. can increase or decrease
D. does not change
B
the sample variance is an unbiased estimator of the population variance
A. when dividing SS by n
B. when dividing SS by Df
C. when dividing SS by n-1
D. both B and C
D
the following samples were selected by two researchers. which is associated with a smaller standard error of the mean?
researcher a n=25, u=5, o=7
researcher b n=25, u=32, o=7
A. researcher a
B. researcher b
C. they both have the same standard error
C
increasing the number of observations or a samples in a study will decrease the standard error (standard error of the mean). this is known
A. bob (not the right answer)
B. the law of diminishing returns
C. the theoretical law of estimates
D. the law of large numbers
D
a researcher selects a sample of 625 participants from a population with a mean of 120 and a stand. dev. of 25. the probability of selecting a sample mean that is larger than 125 is close to zero.
A. true
B. false
A
the standard error of the mean is the standard deviation in a sampling distribution of sample means
A. true
B. false
A
if a researcher selects a sample of 64 participants from a population with a variance of 16, then the standard error of the mean will be 2.0
A. true
B. false
B
the sample mean is an unbiased estimator of the population mean
A. true
B. false
A
there are more possible samples that can be selected using theoretical sampling than using experimental sampling for any sample size greater than 1.
A. true
B. False
A
the mental limit theorem sates that the sample mean will equal the population mean on average
A. true
B. false
B
the sampling distribution of the mean has minimum variance
A. true
B. false
A
the sampling distribution of the mean is a distribution of all the possible samples of a particular size that can be selected from a given population
A. true
B. fasle
A
Researchers were to table 9 participants from a population with ANS either deviation of three. About 40% of the sample means in the sampling distribution should be between a sample mean of
A. 6 and 8
B. 5 and 6
C. 9 and 10
D. 10 and 11
C
There are 25 possible Samples of size 2 that can be selected for a population of five people using theoretical sampling
A. True
B. Fasle
A
A researcher states that a sample of 100 shoppers spend 112+_40 (M +_ SEM) dollars on groceries each week. Which value is the standard error of the mean?
A. 112
B. 40
C. 100
D. The standard error of the mean is not reported in the article
B
The average sample variance equals the population variance when dividing SS by df
A. True
B. False
A
Researcher reports the following data for the number of beds made of a sample of them sold in Goshen. Based on the table, what is the probability that an item had seven beds made on that?
A. 5
B. 10
C. .10
D. .25
D
Two outcomes are said to be mutually exclusive when
A. Probability of two outcomes or cream together to equal to zero
B. Probability of the occurrence of one outcome has no effect on the probability of the second outcome
C. The probability of the two outcomes occurring together is greater than zero
D. Probability of the two outcomes occurring together sums to one.
A
In a game the probability of winning money is p=.16 the probability of losing money is p=.54 and the probability of breaking even is p=.30. What is the probability of winning or losing money in this game?
A. .16
B. .54
C. .70
D. 1.00
C
Which rule states that went to outcomes are independent, the probability that these outcomes occur together is the product of their individual probabilities?
A. Additive rule
B. Multiplicative rule
C. Both A and B
D. None of the above
B
A researcher Reports that the probability of a college student living on campus is P equals 30. If a small local college has 2000 students in rolled, then what is the Steeler deviation of college students living on campus? Hint this is a binomial probability distribution
A. 471.2 students
B. 21.7 students
C. 760 students
D. Not enough info
B
A researcher determines that the probability of the missing class among students at a local school is P equals .16. Assuming the school has 300 students in rolled, how many students can we expect to his class on a given day? Hint this is a binomial probability distribution
A. 252 students
B. 48 students
C. 16 students
D. Not enough info
B
If the standard deviation of a probability distribution is ninth in the variance is
A. 3
B. 9
C. 81
D. Unknown
C
When the probability of one outcome changes depending on the occurrence of a second outcome, these outcomes are referred to as:
A. Mutually exclusive
B. Complimentary
C. Independent
D. Conditional
D
The probability of a college student being employed is p=.35. The probability of a student being employed and dropping out of college is p=.20. Hence the probability of a student dropping out of college, given that he or she is employed is:
A. .07
B. .57
C. .55
D. Not enough info
B
The following dist. Approximates a:
Normal distribution
The normal distribution has all the following characteristics except:
A. The mean can be any number
B. It is mathematically defined
C. The total area under the curve is greater than 1.0
D. The mean, median, and mode are equal
C
What is the implication for tails of a normal dist. Being asymptotic?
A. That scores above the mean are distributed the same as scores below the mean
B. That extreme scores are possible in a normal distribution
C. That there are an infinite # or possible normal dist.
D. That this characteristic has not practical implication
B
Bayes' Theorem is often applied to a variety of ___ probability situations including those related to statistical inference
A. Generic
B. Absolute
C. Conditional
D. Fixed
C
The probability of making zero to two errors per 1,000 keystrokes is .43 and the probability of making three to five errors per 1,000 keystrokes is .28. Find the probability associated with making at most five errors.
A. .29
B. .43
C. .57
D. .71
D
The normal dist. Is symmetrical which means.
A. Scores above the mean are distributed the same as scores below the mean
B. Extreme scores are possible in a normal distribution
C. There are an infinite number of possible normal dist.
D. This characteristic has no practical implication
A
The standard normal distribution is normally distributed with a mean of __ and a variance of __
A. 0;1
B. 1;0
C. Any value; any positive value
D. Any positive value; any value
A
The unit of measurement distributed along the x axis of a standard normal distribution is referred to as a
A. Standardized score
B. X score
C. Normalized deviation
D. Z score
D
What is the z score for the scores of the bottom 5%
A. 1.645
B. -1.645
C. .4801
D. -.050
B
Which proportion is Large's in the z distribution?
A. The proportion of the are above the mean
B. Between z = +1 and z = -1
C. Greater than z=1.0
D. Less than z=0
B
Scores far from the mean are located ___ of a normal dist.
A. Body
B. Tails
C. Most sensitive areas
D. Most uncertain areas
B
The normal distribution has a mean equal to 53. What is the stupid deviation of this normal distribution of 2.5% of the proportion under the curve lies to the right X equals 66.72?
A. -7.00
B. .14
C. 7.00
D. 49.00
C
How is the standard error of the mean typically reported in the graph?
A. Using error bars
B. By plotting sample means
C. By listing groups names along the x axis
D. It is never reported in a graph
A
Each of the following statements are true except
A. Increasing the sample size will decrease standard error
B. The larger the sample size the larger the standard error
C. The larger the standard deviation in the population the larger the standard error
D. Both b and c
B
Regardless of the shape of the distribution in the population the sampling distribution of the sample carriages approximates a
A. Normal distribution
B. Positively skewed distribution
C. Negatively skewed distribution
D. Multimodal distribution
B
Researchers Lexi's symbol of 16 participants from a population with a variance of four what is the standard error of the mean
A. Less than 1
B. Equal to 1
C. Greater than 1
D. Not enough info
A
Suppose that a researcher selects a sample of participants from a population. If the shape of the distribution in this population is positively skewed then what is the shape of the sampling dist. Of sample means?
A. Approximately positively skewed
B. Approximately negatively skewed
C. Approximately normally distributed
D. Not enough info
C
For the experimental sampling strategy
A. The order in which a participant is selected matters
B. Sampling is with replacement
C. Sampling is without replacement
D. Participants are not sampled but sampled from other samples already drawn
C
What values are distributed along the x axis for sampling dist. Of the sample mean?
A. Scores
B. Sample means
C. Sample variances
D. Both b and c
B
What values are distributed along the x axis for sampling dist. Of the sample variance?
A. Scores
B. Sample means
C. Sample variances
D. Both b and c
C
The ________ theorem explains that the shape of a sampling dist. Of sample means tends toward a normal dist. Regardless of the dist. In the population
Central limit
;