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103 Cards in this Set
- Front
- Back
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The GPA of 7 randomly chosen students from your statistics class are : 3.14, 2.37, 2.94, 3.60, 1.70, 4.00, 1.85. The mean is:
A. 2.8 B. 2.94 C. 3.6 D. None of the above |
A. 2.8
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You record the age, marital status, & earned income of a sample of 1,463 women. The # of variables you have recorded is:
A. 1,463 B. Four - age, income, marital, # of women C. Three - age, income, marital status D. Two - age & income E. None of the above |
C. Three - age, income, marital status
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A professor records the values of several variables for each student in class. These include the variable listed below. Which are categorical?
A. Score on final (out of 100) B. Final Grade (A, B, C) C. Total # of points earned in class D. # of classes missed E. None of the above |
B. Final Grade
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The mean age of 2 people in a room is 20 years. A 50 year old enters. What is the mean now?
A. 20 B. 30 C. 33.3 D. 35 E. None |
B. 30
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A sports columnist wishes to falsely portray that baseball players are overpaid. Which center should she choose as the average of MLB players?
A. Mean B. Median C. Either, they will be equal D. Neither, both will be lower E. None |
A. Mean
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A distribution of 6 scores has a median of 21. If highest score increases 2 points, the median will be:
A. 21 B. 21.5 C. 24 D. Cannot be determined E. None of the above |
A. 21
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If you are told that a set of data has a mean of 25 & variance of 0, you can conclude:
A. There is only one observation B. There are no observations C. All observations are 25 D. Someone made a mistake E. None of the above |
C. All observations are 25
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Of the following measures, mean, median, IQR, & standard deviation, which are resistant?
A. Mean & median B. Median & IQR C. Mean & Std. Deviation D. Median and Standard Deviation E. None |
B. Median and IQR
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The quantity ∑( xi - xbar ) is not used for variation because:
A. It is always 0 B. It's always negative C. It's too difficult to use D. It's always positive E. None |
A. It is always 0
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The variance of 1, 2, 3, 4, & 5 is:
A. 2.5 B. 9 C. 10 D. 13.3 E. 55 |
A. 2.5
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Which is likely to have a mean smaller than median?
A. Salaries of NFL players B. Scores of students (out of 100) where most get perfect scores but few do bad C. Prices of homes D. None of these |
B. Scores of student, most perfect, some bad.
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If you add 5 to each value, the standard deviation will:
A. Decrease 5 B. Increase by 5 C. Stay the same D. Depends E. None |
C. Stay the same
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If you multiply 5 to each value, then the standard deviation will be:
A. Unchanged B. 1/5 as large C. 5x as large D. Depends E. None |
C. 5x as large
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Which are categorical?
A. # of people watching TV B. Ages of all people C. # of times shown D. Name of the show E. None |
D. Name of the show
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The heights of American men aged 18-24 are normally distributed w/ mean 68 inches & std. deviation 2.5 inches. Half of all young men are shorter than:
A. 65. 5 B. 68 C. 70.5 D. Can't tell E. None |
B. 68
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The heights of American men aged 18-24 are normally distributed w/ mean 68 inches & std. deviation 2.5 inches. Only about 5% of young men have heights outside the range
A. 65.5 to 70.5 B. 63 to 73 C. 60.5 to 75.5 D. 58 to 78 E. None |
B. 63 to 73
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What is a smooth curve which approximates the shape of a histogram known as?
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Density Curve
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Describe a normal density curve
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Symmetric, Peak is equal to the mean, spread is proportional to standard deviation
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The area under a standard curve corresponding to -.3 < z < 1.6
A. .3273 B. .4713 C. .5631 D. .9542 E. None |
C. .5631
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Are the mean and median equal under a normal density curve?
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Yes
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16 oz bag of cookies are produced w/ mean of 16.1 & Std. deviation of .1. The % if bags that will be between 16.0 and 16.1 is:
A. 10 B. 16 C. 34 D. 68 E. None of the above |
C. 34
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16 oz bag of cookies are produced w/ mean of 16.1 & Std. deviation of .1.
What percent is underweight? A. 10 B. 16 C. 32 D. 64 E. None |
B. 16
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What is true of any density curve?
A. Bars must be equal width B. Its symmetric |
A. Bars must be equal width
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y = 10 + .9x
x = First Test y = Exam Score What is her score on the final if Carla made a 95 on her first test? If she made a 98 on her final, what is her residual? (The Actual - The Final) |
Final = 95.5
Residual = 2.5 |
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A. Correlation between position and weight: r = .54
B. Correlation between planting rate and corn yield: r = .23 C. Correlation between gas mileage and weight: r = .71 mpg D. Correlation between height and age is 1.09 E. Correlation r = -.63 between gender and political party |
B. R = .23 b/t planting rate and corn yield
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The difference between the observed and predicted gives you:
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Residual
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r^2 measures what?
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the fraction of variation in values of y that is explained by LSR on the other
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When the correlation is -1.08 then:
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You need a new statistician
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Is a line a good model for a residual plot with a curved pattern?
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No
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When the trunks of a tree are 4, 2, 8, 6, 10, and 6 and the tree heights are 8, 4 , 18, 22, 30, and 8, what is the LSRL? What is the height when the trunk is 7 inches?
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LSRL - y = -3.6 + 3.1x
x = 7 inches y = 18.1 |
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What do we call any individual points with unusually large values?
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Outliers
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If removing an observation would have marked change on position of LSRL, what is the point called?
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Influential
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What is predicting values of y for values of x outside the observed data known as?
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Extrapolation
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A Sample that consists of the entire population is:
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A mistake
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When 228 letters are received, 193 opposed legislation. What is the population?
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228 letters
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What do we call any individual points with unusually large values?
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Outliers
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If removing an observation would have marked change on position of LSRL, what is the point called?
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Influential
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What is one method for improving the accuracy of a sample?
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Use large sample sizes
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What is predicting values of y for values of x outside the observed data known as?
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Extrapolation
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Control groups are used in experiments in order to:
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control the effect of lurking variables such as the placebo effect
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A Sample that consists of the entire population is:
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A mistake
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Experimental units
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The 2 temp and 3 stirring rates
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When 228 letters are received, 193 opposed legislation. What is the population?
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228 letters
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Factors
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Batches of feedstock
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What is one method for improving the accuracy of a sample?
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Use large sample sizes
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Response Variable
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None of the above
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Control groups are used in experiments in order to:
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control the effect of lurking variables such as the placebo effect
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What do we call any individual points with unusually large values?
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Outliers
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Experimental units
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The 2 temp and 3 stirring rates
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If removing an observation would have marked change on position of LSRL, what is the point called?
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Influential
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Factors
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Batches of feedstock
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What is predicting values of y for values of x outside the observed data known as?
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Extrapolation
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Response Variable
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None of the above
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A Sample that consists of the entire population is:
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A mistake
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When 228 letters are received, 193 opposed legislation. What is the population?
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228 letters
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What is one method for improving the accuracy of a sample?
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Use large sample sizes
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Control groups are used in experiments in order to:
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control the effect of lurking variables such as the placebo effect
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Experimental units
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The 2 temp and 3 stirring rates
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Factors
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Batches of feedstock
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Response Variable
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None of the above
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Treatments
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6
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Experimental Units
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None of the above
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What is the probability of a random phenomenon?
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Any number as long as it is between 0 and 1
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{Yes, no, maybe} Which is an assignment of probabilities for this sample space?
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.4, .4, .2
Has to equal 1 |
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52 Cards in a deck, what is the probablity that it is not a heart?
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p = .75
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Any match the prob of winning is .6. What is the probability of winning the next two matches?
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p = .36
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P(A) = .24 P(B) = .54
What is P(A or B)? |
P(A or B) = .6352
or .6504 |
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Disjoint
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# above 100 and less than -200
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26% of labor force have @ least 4 years of college and 15% of labor force work as laborers or vehicles. Can you conclude 4% are college laborers or operators?
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No b/c they are not independent
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Brown = .3
Red = .2 Yellow = .2 Green = .2 Orange = .1 What is the p of drawing blue? |
It is impossible to draw blue
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When two dice are rolled, what is the p of a sum greater than nine?
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1/6
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When two dice are rolled, a sum less than 4 or greater than 9?
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1/4
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A coin is tossed 5 times. What is the p of getting at least one tail?
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31/32
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A coin is tossed 5 times. What is the probability of getting 4 heads?
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5/32
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P( A U B) = S
P(A & Bcomp) = .25 P(Acomp) = .35 What is P(B)? A. .35 B. .4 C. .65 D. .75 E. None |
D. .75
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red) = |
3/5
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Even #) = |
1/2
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red and Even) = |
3/10
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red or Even) = |
4/5
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Neither Red nor even) = |
1/5
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P( Even l Red) = |
1/2
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red l Even) = |
3/5
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( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P( <4 l odd) |
4/5
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What does the law of large numbers say?
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The average will get closer to M as we observe x more and more often
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P(X=0) = .2
P(X=1) = .6 P(X=2) = .2 What is the mean of probability distribution? |
1
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P(X=0) = .2
P(X=1) = .6 P(X=2) = .2 What is the variance? A. 1 B. .63 C. .5 D. .4 |
D. .4
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The total # of calories are as follows:
1 cup of cereal = 110 1 cup of milk = 140 What is the mean of z when there is a half cup of milk? A. 110 B. 140 C. 180 D. 250 E. 195 |
C. 180
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20% of students experiece anxiety. In a random sample of 10 students, what is the probability of exactly 2 having anxiety?
A. .3020 B. .2634 C. .2013 D. .5 E. none of the above |
A..3020
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20% of students experiece anxiety. In a random sample of 10 students, what is the Std. deviation of # experiencing anxiety?
A. .0160 B. 1.265 C. .2530 D. 1 E. .2070 |
B. 1.265
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40% of houses = $70,000
Sample = 4 Houses What is the prob that 2 or more have an annual income over $70,000? A. .3456 B. .4000 C. .5000 D. .5248 |
D. 5248
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18 Chips, 90% met specifications, How many met the specifications?
A. 16.20 B. 1.62 C. 4.02 D. 16 |
A. 16.20
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P that 3 year old batteries still work is .8. The machine needs 4 batteries to work. What is the probability that 4 3 year old batteries work?
A. .9984 B. .8000 C. .5904 D. .4096 |
D. .5904
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20% of trucks will fail. How many trucks will pass until one fails?
A. 2 B. 5 C. 5 D. 20 |
A. 2
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2% of a product are defective, greater than 10?
A. 1.024 B. 5.12 C. .1829 D. .81707 |
D. .81707
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Is 92% a statistic or parameter?
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Statistic
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46%, own VCRs, 100 are to be asked, what is the mean?
A. 46 B. .46 C. .00248 D. .05 |
A. 46
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Standard deviation = σ
What is the mean of 100? A. σ B. 100σ C. σ/10 D. σ/100 E. 1 |
C. σ/10
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When a sample matches a population, is it biased or unbiased?
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Unbiased
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95% Confidence Level, σ = 10, Sample Size is 50
What is z*? A. 1.645 B. 2.009 C. 1.960 D. .8289 E. .8352 |
C. 1.960
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90% Confidence Interval
σ = 100 Margin of Error = 10 What is sample size? A. 16 B. 271 C.36 D. 1476 |
B. 271
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Ho = 2
Ha = M ≠ 2 z = 140 What is the p-value? |
,16
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The z* for 70% is
A. -.5244 B. 1.036 C. .5244 D. .6179 |
B. 1.036
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How does one determine outliers?
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Multiply IQR by 1.5 and check in range
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