data analysis

Question 1

what is a p value?

Answer 1

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

Question 2

if p is larger than 0.05

Answer 2

difference is NOT statistically significant, reatain the null hypothesis

Question 3

is p is smaller than 0.05

Answer 3

difference is statistically significant, reject the null hypthesis

Question 4

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

Answer 4

false negative

Question 5

what is a false negative

Answer 5

accepting a null hypothesis when there actually IS a real effect

Question 6

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

Answer 6

positive

Question 7

what is a false positive

Answer 7

rejecting a null hypothesis when there is NO real effect

Question 8

what does parametric mean?

Answer 8

it adhears to normal distribution

Question 9

what is quantitative data

Answer 9

numerical

Question 10

what is continous data

Answer 10

can be measured

Question 11

what is discrete date

Answer 11

only certain values ie shoe size

Question 12

what is categorical data

Answer 12

category type of qualitiative data

Question 13

what is a 95% ci

Answer 13

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

Question 14

when would we use an unpaired t test

Answer 14

analysing parametric data from two independant samples

Question 15

what is a mann u whitney test used for?

Answer 15

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

Question 16

what is a one tailed t test

Answer 16

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.

Question 17

what is a two tailed t test

Answer 17

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.

Question 18

how to we determine if a data set is parametric?

Answer 18

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?

Question 19

what is a paired t test

Answer 19

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

Question 20

what paired t test would you use for non parametric data

Answer 20

wilcoxon signed rank test

Question 21

when would you use a wilcoxon signed rank test

Answer 21

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.

Question 22

what test would determine if data is parametric?

Answer 22

Shapiro-Wilk test)

Question 23

what does anova stand for

Answer 23

analysis of variance

Question 24

what is anova

Answer 24

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

Question 25

what is a one way anova

Answer 25

Studies with 3 or more varying conditions on a single continuous variable
(e.g. the effect of varying
treatments on blood pressure)

Question 26

what does the first step of anova test for , what more do you need ?

Answer 26

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

Question 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;

Answer 27

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.

Question 28

what does the anova test assume?

Answer 28

data is parametric and independant (unpaired)

Question 29

what tests would you use for categorical data anyalysis?

Answer 29

McNemars test
Fishers exact test
Pearsons chi-squared test