data analysis Flashcards

1
Q

what is a p value?

A

the calculated probability that there is no genuine difference between the groups. basically the strength of avidence against the null hypotheisis

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2
Q

if p is larger than 0.05

A

difference is NOT statistically significant, reatain the null hypothesis

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3
Q

is p is smaller than 0.05

A

difference is statistically significant, reject the null hypthesis

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4
Q

a smaller alpha value ie 0.01 is likely going to lead to a type two false ?

A

false negative

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5
Q

what is a false negative

A

accepting a null hypothesis when there actually IS a real effect

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6
Q

a larger alpha value ie 0.1 is likely going to lead to a type one false ?

A

positive

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7
Q

what is a false positive

A

rejecting a null hypothesis when there is NO real effect

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8
Q

what does parametric mean?

A

it adhears to normal distribution

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9
Q

what is quantitative data

A

numerical

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10
Q

what is continous data

A

can be measured

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11
Q

what is discrete date

A

only certain values ie shoe size

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12
Q

what is categorical data

A

category type of qualitiative data

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13
Q

what is a 95% ci

A

Measure of precision where 95% of the real answers lie between two given values

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14
Q

when would we use an unpaired t test

A

analysing parametric data from two independant samples

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15
Q

what is a mann u whitney test used for?

A

unpaired, independant non parametric data
non-parametric statistical test used to compare the medians of two independent groups (samples) for ordinal or continuous data.

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16
Q

what is a one tailed t test

A

One-tailed t-test: Used when you have a specific direction in mind and want to test for a difference in that direction only. For example, if you think Group A will perform better than Group B, you would use a one-tailed test.

17
Q

what is a two tailed t test

A

Two-tailed t-test: Used when you don’t have a specific direction in mind and want to test for a difference in either direction. It’s more conservative and covers the possibility of differences in both directions.

18
Q

how to we determine if a data set is parametric?

A

Subjectively evaluate the distribution of data (or data from previous studies) using a
histogram. E.g. is the shape correct? Is it symmetrical, skewed, what level of kurtosis is
there?

19
Q

what is a paired t test

A

statistical test used to compare the means of two related (paired) groups for a continuous outcome variable.
When to use: When you have paired data (related samples) and you want to determine if there is a significant difference in the means between the paired groups.

ie before and after

20
Q

what paired t test would you use for non parametric data

A

wilcoxon signed rank test

21
Q

when would you use a wilcoxon signed rank test

A

for non-parametric statistical test used to compare two related (paired) groups for a continuous outcome variable when the assumptions for the paired t-test are not met.

22
Q

what test would determine if data is parametric?

A

Shapiro-Wilk test)

23
Q

what does anova stand for

A

analysis of variance

24
Q

what is anova

A

standard approach used for statistical analysis of studies involving multiple
comparisons (and at least one continuous variable)

25
what is a one way anova
Studies with 3 or more varying conditions on a single continuous variable (e.g. the effect of varying treatments on blood pressure)
26
what does the first step of anova test for , what more do you need ?
first step only assesses whether there is a statistically significant difference between any of the groups; it doesn’t indicate which groups are different (i.e. which pairs of groups), particularly the specific pairwise comparisons that are the focus of the study you need post tests
27
first step of anova only assesses whether there is a statistically significant difference between any of the groups; it doesn’t indicate which groups are different (i.e. which pairs of groups), particularly the specific pairwise comparisons that are the focus of the study, the tests are;
Tukey’s test is used when a study requires pairwise comparison of every possible combination of groups. * Dunnett’s test is used when each pairwise comparison involves one specific group (e.g. a control group). * Bonferroni’s test (or “Bonferroni correction”) is used when the specific pairwise comparisons required do not follow a particular pattern.
28
what does the anova test assume?
data is parametric and independant (unpaired)
29
what tests would you use for categorical data anyalysis?
McNemars test Fishers exact test Pearsons chi-squared test