stats tests Flashcards

1
Q

what is the null hypothesis

A

a hypothesis against a research question
claims no difference in result and difference is an error

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2
Q

what is the p- value

A

the probability that the null hypothesis is correct

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3
Q

what is an alpha-level

A

threshold level for a p-value usually 0.05 so is p-value is <0.05 reject null hypothesis if >0.05 accept null hypothesis

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4
Q

what is a type 1 error

A

false positive
reject null hypothesis when true

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5
Q

what is a type 2 error

A

false negative
accept null hypothesis when false

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6
Q

what kind of data is used in a binomial test

A

dichotomous, yes/ no

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7
Q

What are the three types of binomial test

A

one-tailed where observed is < expected
(cumulative probability 0 to observed)
one-tailed where observed is > expected
(1- cumulative probability from observed max)
two-tailed cumulative probability distance from mean

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8
Q

what is confidence level

A

a range of plausible values associated with confidence level (95%)

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9
Q

when do you use a chi-square goodness of fit test

A

proportions with more than two levels

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10
Q

when should chi-square test of association be used

A

comparing proportion across two or more groups

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11
Q

when should McNemar’s test be used

A

when there are two dichotomous variables e.g. 2by2 contingency table and paired samples measuring proportions

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12
Q

When should a one-sample t-test be used

A

comparing a measure to a fixed value

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13
Q

when should a two sample t-test be used

A

when comparing a measure across two groups independently

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14
Q

when should a paired t-test be used

A

when data can be paired between to groups and are comparing a measure

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15
Q

what is the difference between binomial test and chi squared goodness-of-fit

A

both compare proportions however chi-square can have more than two categories (not dichotomous)

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16
Q

What is chi-squared test of association also known as

A

test of independence

17
Q

what are t-tests used for

A

measure difference in groups of measure
compare means of populations

18
Q

what kind of data is used for t-tests

A

interval or ratio

19
Q

what nominal test does one-sample t-test correspond to

A

binomial
chi-square goodness of fit

20
Q

What nominal test does independent (unpaired) sample t-test correspond to

A

chi-square test of association

21
Q

what nominal test does paired samples t-test correspond to

A

McNemar’s test

22
Q

what does one sample t-test compare

A

compares mean of one sample group to a fixed value

23
Q

What do independent samples t-test compare

A

observed difference between the means of two independent samples or categories

25
What doe paired sample t-test compare
mean difference of one group measure on two occasions
26
What assumptions are made by t-tests
normality equality of variance
27
What is central limit theorem
one of the most important theorems in data science if you take n sample from distribution and calculate means will still be normally distributed shows sample is large enough
28
what are parametric tests
statistical tests based on an assumption of normality
29
how is normality tested
Shapiro-Wilk Indicated by a low p-value
30
what test should be used if variance isn't equal
Welch's test
31
what is the t-score dependent on
degree of freedom and sample size
32
what does a greater t score indicate
greater difference
33
how is a one sample t-test result reported
mean, standard deviation then, t(x) = y, p= .z
34
how is independent samples t-test reported
mean, SD, t(x) = y, p= z
35
how is paired samples t-test reported
mean and SD, t(x) = y, p= z