basic quant Flashcards

(63 cards)

1
Q

mode

A

value that occurs the mode frequently

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2
Q

which measure of central tendency uses nominal variables, only?

A

mode

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3
Q

mean

A

the average

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4
Q

median

A

the exact middle of distribution of scores, always.

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5
Q

which measure of central tendency uses interval-ratio or ordinal variables?

A

median

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6
Q

which measure of central tendency uses interval-ratio, only?

A

mean

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7
Q

what is a proportion?

A

the fraction of the total that possesses a certain attribute

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8
Q

What is a theory?

A

A theory is a fairly elaborate explanation of the relationship between two or more variables.

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9
Q

what is a hypothesis?

A

a hypothesis offers tentative answers to research questions

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10
Q

what are the three main methods of collecting data?

A

telephone, mail (address), and direct observation

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11
Q

cause and effect relationships require ___ (3 aspects) before casualty is established

A

time order, non-spuriousness, correlation

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12
Q

what is a nominal variable

A

a variable associated with categorization. order does not matter and cannot be quantified. ex: age, gender, race

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13
Q

what is an ordinal variable

A

a variable that categorizes with an implied order. often uses likert scale. other ex: social class

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14
Q

what is an interval-ratio variable

A

a fully quantifiable variable where order is characterized by equal units or intervals between categories. ex: temperature, number of children, ages in a frequency distribution

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15
Q

what is an interval-ratio variable

A

a fully quantifiable variable where order is characterized by equal units or intervals between categories. ex: temperature, number of children, ages in a frequency distribution

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16
Q

are nominal variables discrete or continuous?

A

discrete

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17
Q

are ordinal variables discrete or continuous?

A

discrete

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18
Q

are interval-ratio variables discrete or continuous

A

it depends

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19
Q

which variable is the only kind that can be continuous – nominal, ordinal, or IV?

A

interval-ratio

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20
Q

Simple random sampling

A

every number in the population has an equal (nonzero) probability of being selected into the sample

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21
Q

systematic random sampling

A

every “k-th” (interval) number of the population after the first number is selected into the sample

ex: k = 8 –> 1, 8, 16, 24…

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22
Q

stratified sample

A

involves dividing the entire population into homogeneous groups called strata

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23
Q

cluster sample

A

dividing a population into clusters, and then randomly selecting a sample of these clusters

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24
Q

pie charts are suited to which level of measurement?

A

nominal and ordinal

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25
histrograms are suited to which level of measurement?
interval-ratio
26
if N<30, do we use t-chart or z-chart?
t-chart
27
if N>30, do we use t-chart or z-chart
z-chart
28
what is the difference between standard error and standard deviation?
standard error is the square-root of std. dev
29
the larger the standard error, the further the result will be from the true population
true
30
what is "true population"
mu
31
what is probablity
the measure of uncertainty
32
what are the steps to hypothesis testing?
1. state assumptions 2. State Ho and Ha 3. Define sample distribution, critical region(s) 4. Compute test statistic 5. Make a decision and state conclusion
33
complete the sentence: If z-observed is greater than z-critical, you ___ the null hypothesis
If z-observed is greater than z-critical, you reject the null hypothesis
34
complete the sentence: If z-observed is less than z-critical, you ___ the null hypothesis
complete the sentence: If z-observed is less than z-critical, you "fail to reject" the null hypothesis
35
complete the sentence: Using confidence intervals, you are confident that...
when using confidence intervals, you are XX% confident that (given pop) is between {XX to XX}
36
interval question: the fewer the sample size...
the greater the interval
37
which level of measurement uses IQR?
normally interval-ratio, but also ordinal
38
which level of measurement uses range?
interval-ratio
39
which level of measurement uses standard deviation?
interval-ratio
40
are population mean (mu) and standard deviation (sigma) variables?
no, they are constants/parameters
41
sample mean (y-bar), sample, variance (sample-squared) are referred to (estimators or parameters?)
estimators
42
mean uses which level of measurement?
interval-ratio
43
negatively skewed distribution = the mean is ___ than the median
less than
44
positively skewed distribution -- the mean is ___ than the median
greater in value
45
unskewed distribution -- mean is ___ median
equal to
46
measures of central tendency
mean, mode, median
47
level of measurement for chi-square for DV
nominal or ordinal
48
is correlation a sufficient condition of causality?
no (but it is necessary)
49
use of z-scores
1. Find various areas under the normal curve 2. Comparison of scores with different means and standard deviations 3. Computing percentile rankings
50
point estimates need to be
unbiased, efficient, and consistent
51
assumptions for single mean (hypothesis testing)
normal distribution, random sample, interval/ratio level of measurement.
52
assumptions for single proportion (hypothesis test)
normal distribution, random samples, nominal level of measurement.
52
assumptions for single proportion (hypothesis test)
normal distribution, random samples, nominal level of measurement.
53
type 1 error
alpha error, false positive, the probability of rejecting a null hypothesis that is, in fact, true. (reject the null hypothesis)
54
type 2 error
beta error, the probability of failing to reject a null hypothesis that is, in fact, false. fail to reject the null hypothesis
55
assumptions for two independent means (hypothesis testing)
normal distribution, independent random samples, interval/ratio level of measurement
56
assumptions for two proportions
Independent random samples, nominal level of measurement, normal sampling distribution.
57
when to use ANOVA?
Use when the independent variable has three or more categories, and the dependent variable is Interval Ratio.
58
what is the f-test?
The F-test is an overall test of the null hypothesis that group means on the dependent variable do not differ.
59
how to construct a contingency table? (aka a matrix?)
IV = column; DV = rows
60
how to construct a contingency table? (aka a matrix?)
IV = column; DV = rows
61
logic of regression is to estimate
strength, direction and nature, and magnitude
62
Population Regression Equation:
y = alpha + Betax1