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103 Cards in this Set

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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
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
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
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
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
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
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
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
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
The variance of 1, 2, 3, 4, & 5 is:
A. 2.5
B. 9
C. 10
D. 13.3
E. 55
A. 2.5
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.
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
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
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
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
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
What is a smooth curve which approximates the shape of a histogram known as?
Density Curve
Describe a normal density curve
Symmetric, Peak is equal to the mean, spread is proportional to standard deviation
The area under a standard curve corresponding to -.3 < z < 1.6
A. .3273
B. .4713
C. .5631
D. .9542
E. None
C. .5631
Are the mean and median equal under a normal density curve?
Yes
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
16 oz bag of cookies are produced w/ mean of 16.1 &amp; Std. deviation of .1.
What percent is underweight?
A. 10
B. 16
C. 32
D. 64
E. None
B. 16
What is true of any density curve?
A. Bars must be equal width
B. Its symmetric
A. Bars must be equal width
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
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
The difference between the observed and predicted gives you:
Residual
r^2 measures what?
the fraction of variation in values of y that is explained by LSR on the other
When the correlation is -1.08 then:
You need a new statistician
Is a line a good model for a residual plot with a curved pattern?
No
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?
LSRL - y = -3.6 + 3.1x
x = 7 inches
y = 18.1
What do we call any individual points with unusually large values?
Outliers
If removing an observation would have marked change on position of LSRL, what is the point called?
Influential
What is predicting values of y for values of x outside the observed data known as?
Extrapolation
A Sample that consists of the entire population is:
A mistake
When 228 letters are received, 193 opposed legislation. What is the population?
228 letters
What do we call any individual points with unusually large values?
Outliers
If removing an observation would have marked change on position of LSRL, what is the point called?
Influential
What is one method for improving the accuracy of a sample?
Use large sample sizes
What is predicting values of y for values of x outside the observed data known as?
Extrapolation
Control groups are used in experiments in order to:
control the effect of lurking variables such as the placebo effect
A Sample that consists of the entire population is:
A mistake
Experimental units
The 2 temp and 3 stirring rates
When 228 letters are received, 193 opposed legislation. What is the population?
228 letters
Factors
Batches of feedstock
What is one method for improving the accuracy of a sample?
Use large sample sizes
Response Variable
None of the above
Control groups are used in experiments in order to:
control the effect of lurking variables such as the placebo effect
What do we call any individual points with unusually large values?
Outliers
Experimental units
The 2 temp and 3 stirring rates
If removing an observation would have marked change on position of LSRL, what is the point called?
Influential
Factors
Batches of feedstock
What is predicting values of y for values of x outside the observed data known as?
Extrapolation
Response Variable
None of the above
A Sample that consists of the entire population is:
A mistake
When 228 letters are received, 193 opposed legislation. What is the population?
228 letters
What is one method for improving the accuracy of a sample?
Use large sample sizes
Control groups are used in experiments in order to:
control the effect of lurking variables such as the placebo effect
Experimental units
The 2 temp and 3 stirring rates
Factors
Batches of feedstock
Response Variable
None of the above
Treatments
6
Experimental Units
None of the above
What is the probability of a random phenomenon?
Any number as long as it is between 0 and 1
{Yes, no, maybe} Which is an assignment of probabilities for this sample space?
.4, .4, .2
Has to equal 1
52 Cards in a deck, what is the probablity that it is not a heart?
p = .75
Any match the prob of winning is .6. What is the probability of winning the next two matches?
p = .36
P(A) = .24 P(B) = .54
What is P(A or B)?
P(A or B) = .6352
or .6504
Disjoint
# above 100 and less than -200
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?
No b/c they are not independent
Brown = .3
Red = .2
Yellow = .2
Green = .2
Orange = .1
What is the p of drawing blue?
It is impossible to draw blue
When two dice are rolled, what is the p of a sum greater than nine?
1/6
When two dice are rolled, a sum less than 4 or greater than 9?
1/4
A coin is tossed 5 times. What is the p of getting at least one tail?
31/32
A coin is tossed 5 times. What is the probability of getting 4 heads?
5/32
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
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red) =
3/5
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Even #) =
1/2
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red and Even) =
3/10
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red or Even) =
4/5
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Neither Red nor even) =
1/5
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P( Even l Red) =
1/2
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P(Red l Even) =
3/5
( R1, R2, R3, R4, R5, R6, W1, W2, W3, W4)
P( <4 l odd)
4/5
What does the law of large numbers say?
The average will get closer to M as we observe x more and more often
P(X=0) = .2
P(X=1) = .6
P(X=2) = .2
What is the mean of probability distribution?
1
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
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
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
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
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
18 Chips, 90% met specifications, How many met the specifications?
A. 16.20
B. 1.62
C. 4.02
D. 16
A. 16.20
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
20% of trucks will fail. How many trucks will pass until one fails?
A. 2
B. 5
C. 5
D. 20
A. 2
2% of a product are defective, greater than 10?
A. 1.024
B. 5.12
C. .1829
D. .81707
D. .81707
Is 92% a statistic or parameter?
Statistic
46%, own VCRs, 100 are to be asked, what is the mean?
A. 46
B. .46
C. .00248
D. .05
A. 46
Standard deviation = σ
What is the mean of 100?
A. σ
B. 100σ
C. σ/10
D. σ/100
E. 1
C. σ/10
When a sample matches a population, is it biased or unbiased?
Unbiased
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
90% Confidence Interval
σ = 100
Margin of Error = 10
What is sample size?
A. 16
B. 271
C.36
D. 1476
B. 271
Ho = 2
Ha = M ≠ 2
z = 140
What is the p-value?
,16
The z* for 70% is
A. -.5244
B. 1.036
C. .5244
D. .6179
B. 1.036
How does one determine outliers?
Multiply IQR by 1.5 and check in range