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Statistics Flashcards

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1
Q

What is the mean

A

The average. Calculated by: all samples/number of samples. Determines how concentrated the data is

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2
Q

What does the standard deviation show

A

The average distance from samples to a centre value. Determines how a data is spread

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3
Q

What % of data is included in 1, 2, and 3 standard deviations

A 
1SD = 68%
2SD = 95%
3SD = 99%
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4
Q

What is data frequency

A

The number of times that similar data occurs

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5
Q

What is data distribution

A

The shape constructed by data frequencies

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6
Q

What are the 3 data types in statistics

A

Numeric, nominal and ordinal data

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7
Q

What is numeric data

A

Data based on numbers, usually continual e.g. age, mass etc.

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8
Q

What is nominal data

A

Data which can be put into categories without rank e.g. gender, colour, weekday

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9
Q

What is ordinal data

A

Data which can be put into categories with rank e.g. feeling, score systems, visual analogy scale

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10
Q

What is the standard error of mean

A

A method used to estimate the standard deviation of a sampling distribution. Shows the range in which a global mean could fall within. It is the standard deviation of means

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11
Q

How is the standard error of mean calculated

A

SD / root of n (n = sample size)

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12
Q

What is roughly equal to the 95% confidence interval

A

The mean +/- 2SD

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13
Q

What is a confidence interval

A

The range in which the global mean could be within

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14
Q

What is the median

A

The middle number when data is arranged from smallest to largest

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15
Q

What are quartiles

A

Sample values at 25%, 50% (median) and 75%

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16
Q

What is the rule for knowing whether to use the mean or the median value in data analysis

A

If the data has normal distribution, use the mean, If the data does NOT have a normal distribution, use the median

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17
Q

What values can a boxplot display

A

The median, quartiles, and extreme values within a category

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18
Q

What value does a pie chart display

A

The percentages of data

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19
Q

What values do error bars show

A

The mean, and 95% confidence interval or SD of the data

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20
Q

What do scatter/dot plots show

A

The relationship between two variables i.e. if they are correlated or not

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21
Q

What is the definition of statistics

A

A subject exploring the concise but most important information from a huge set of data using a small set of data

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22
Q

What is sampling

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A

Randomly taking a small set of data from a huge set of data to be investigated

23
Q

What are 2 key components of sampling

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A

Randomisation and size

24
Q

What is the difference between independent and dependent samples

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A

Independent samples measurements have no effect on each other whereas depended measurements do. For examples, if a subject is tested twice, the two sets of data are depended e.g. pre- and post-operative measurements. In comparison, if different subjects are tested using the same equipment the data is still independent e.g. blood pressure in different age groups

25
What is used to estimate sample size
Standard deviation from previous or pilot studies, and clinical difference in practice
26
What is a double blind experiment
When both the researcher and patients have no idea what samples they are dealing with
27
What is the skewness coefficient
SC is the measure of the asymmetry of a distribution. If SC = 0 then the data has exact normal distribution. If SC > 0 then data has a long right tail. If SC < 0 then data has a long left tail. If SC > 2 then data is NOT normal distribution
28
What does it mean if the dots on a P-P plot are around the line
The data is close to standard deviation
29
What value does the Kolmongorov-Smirnov test use
The p value. This test assumes that the data is normal distribution. If <0.05 then the data is NOT normal distribution
30
What is the difference between the data view and the variable view on SPSS
The data view allows you to inspect the actual data, whereas the variable view allows you too see additional information about the data
31
What does the crosstab function on SPSS do
It cross-tabulates two variables, therefore it shows the associations between the data in table form
32
What do the circles and dashes represent on an error bar
The circles represent the mean, and the dashes represent the confidence interval or SD of the data
33
What are the 3 tests that can be used to determine if data is standard deviation
Skewness coefficient, P-P plot or Kolmogorov-Smirnov test
34
If the p value is low (<0.05), what does this mean about two sets of data
There is a significant difference between the two sets of data. Therefore the hypothesis does NOT stand, you can REJECT the hypothesis
35
What p value is classed as being very low
<0.01
36
If the p value is high (>0.05), what does this mean
The two sets of data are not significantly different. This means that the hypothesis DOES stand, you can ACCEPT the hypothesis
37
What is the null hypothesis
That two sets of data are not significantly different
38
Is the t-test a parametric or non-parametric test
Parametric test
39
What must be true about the data for the t-test to be used
Data must be normal distribution, compare only 2 sets of data, and the 2 sets of data compared must have a small sample size
40
What test is used to compare the variance between multiple groups of data
ANOVA
41
What is the definition of variance
How far away samples are from the data centre
42
What are the two categories of variance
Variance within a group shows the differences among samples, whereas the variance between groups shows the differences between groups
43
What is another name for the one-way ANOVA test
The f-test
44
What hypothesis is used in the one way ANOVA test
That the group means are not significantly different
45
If p <0.05 after performing ANOVA, what test do you then have to do
The Post Hoc test. This tests which pair of groups is significantly different
46
What test can be used for data that is nominal or ordinal
Chi-square test. The chi square test compares the similarity between the theoretical and observed distribution to see if a hypothesis stands or not
47
Although the Chi-square test can be used for numerical data, what is a disadvantage
Quantitative information may be lost
48
What is the difference between parametric and non-parametric tests
Parametric test methods use a specific parameter to analyse data and calculate probability. Most of these methods require data to be numeric and normal distribution. Non-parametric test methods directly use non-numeric data to compare sample groups, especially for the ordinal data
49
What 2 things do non-parametric tests usually use to compare the differences between the two
The number of signs and the total ranks in the groups. If the total number of signs or ranks in group 1 is higher than that in group 2, there may be a significant difference between the 2 groups
50
What does the sign test show
If + then the value in group 1 > group 2. If - then the value in group 1 < group 2. The sign test considers which sample is larger, but NOT how much the difference is
51
What is the rank test
Defines each sample with a rank according to its rank position in ALL samples between the two groups when they have been listed in order. It then allows for a comparison of which group has the larger sum of ranks
52
Describe the Wilcoxon signed-ranks test
A non-parametric test used to compare two dependent groups. Has a null hypothesis that two related medians are similar. Its uses are similar to that of the paired t-test, but for NON-normal distribution
53
When would a Mann-Whitney test be used over a Wilcoxon signed-ranks test
When the data being compared is coming from two INDEPENDENT groups

Statistics (1 decks)

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