Exam #1 Flashcards

1
Q

Summation of x divided by n

A

mean

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2
Q
Summation of (x- pop. mean) squared
Summation of (x- sample mean) squared
A

Sum of squares (ss)

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3
Q

SS divided by N

ss divided by N-1

A

variance

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4
Q

square root of variance squared

A

standard deviation

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5
Q

X - pop mean divided by variance

X - sample mean divided by variance

A

z score of individuals

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6
Q

sample mean - population mean divided by (variance divided by square root of sample size)

A

z-score of means

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7
Q

Nominal

A

categorical

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8
Q

ordinal

A

rank order

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9
Q

interval

A

equal distance between measurements

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10
Q

rational

A

meaningful zero

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11
Q

Kurtosis

A

peakedness of the distribution

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12
Q

lepokurtosis

A

a lot of scores in the middle

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13
Q

platykurtosis

A

flat

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14
Q

When do you use the median?

A
  1. skewed/non normal
  2. undetermined values (SAT scores)
  3. open ended items (1,2,3, >4)
  4. ordinal
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15
Q

When do you use a bar graph?

A

Nominal (qualitative) (categorical)

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16
Q

when do you use a histogram?

A

interval or ratio (quantitative)

17
Q

What effects variability?

A
  1. outliers
  2. sample size if really small
  3. stability under sampling
  4. open ended distributions
18
Q

SS interpret

A

Summed squared distance from the mean

19
Q

variance interpret

A

typical squared distance from the mean

20
Q

Standard deviation interpret

A

typical distance between an individual score and an average score

21
Q

sampling error

A

error between a sample statistic and the corresponding population parameter

22
Q

distribution of sample means

A

set of means from all the possible random samples of a specific size selected from a specific population

23
Q

expected value of M

A

the mean of the distribution of sample means, equal to the population mean

24
Q

standard error of M

A

standard deviation of sample mean

variance(m) = variance/ square root of n

25
Central Limit Theorem
normal is n=30 or more
26
what is standard error determined by?
(1) the size of the sample and | (2) the standard deviation of the population from which the sample is selected
27
Law of large numbers
states that the larger the sample size (n), the more probable it is that the sample mean is close to the population mean
28
Use of a sample not randomly selected in an experiment
limits the degree to which the results can be generalized to a population
29
We generally like the standard deviation when we are trying to describe a sample of data because
it is expressed in units of the raw metric
30
SS definition
the sum of the squared deviation
31
variance definition
the mean squared deviation
32
Standard deviation definition
square root of the variance and provides a measure of the standard distance from the mean
33
mean definition
the sum of the scores divided by the number of scores