Stats - 1 Flashcards
What are the definitions of mean and standard deviation? What do they mean in terms of data distribution?
Mean - the average value of the data
SD - The average distance of the data collected from the mean
Mean - how data is concentrated
SD - how data is separated
What are frequency and distribution of data in statistics? What relationship exists between the 2?
Frequency - how many times a value occurs
Distribution - pattern of all samples plotted together
Frequency constructs the distribution
If a huge number of samples are collected with natural characteristics, it will form a normal distribution - what is this? At the peak of this distribution, what value is expected?
bell curve
at the peak, the value is the mean
in normal distribution, how much data is included in mean +1, 2 and 3 standard deviations?
68%
95%
99%
What kind of files can be imported into SPSS?
excel
txt
What 3 data types are there in statistics?
numeric
ordinal
nominal
What data characteristics can be shown in statistics with a histogram?
frequency and distribution
What can users do with the variable view interface?
define variables and create a data table for them
in SPSS, what can users do with the data view interface?
edit data
import data
In statistics what is the definition of the median? what is the difference between mean and median?
Median is the middle value. Either average of the two middle numbers or the middle number once data has been numerically ordered
mean is not a sample value, median is.
What are the meanings of maximum and minimum in sample data?>
the top and bottom value collected
What can users do with the crosstab function in SPSS?
Can enter two variables into a table and calculate a chi-square for them
In the use of error bars on graphs, what do the circles and dashes represent?
circle - mean
dash - SD, SEM
What chracteristics from two variables can be shown using the scatter dot graph?
trend and association between two variables
What type of files can be exported from SPSS?
excel txt word file graph html
If two sets of sample data have different means, are their global means significantly different? why?
Not sure - it could be the sampling or the research method causing the difference
In test of hypothesis, what are primary/null hypotheses?
no significant difference between groups i.e. p >0.05
What significance levels are normally used in test of the hypothesis?
p >0.05 signifies no significant difference between data sets
When comparing two sets of data, under what condition are two groups of data considered to be significantly different in terms of statistics?
p<0.05
What do single and double asterisks mean in terms of statistics?
- p<0.05
** - p<0.01
Under what condition is the primary hypothesis accepted?
p>0.05
What main indices will influence the results of a test of hypotheses?
mean
sample size
standard deviation
significance level (p value)
In which situations can a t-test be applied?
numeric data with normal distribution and a small sample size
If a group of subjects are measured twice in a time interval, are the results dependent or independent?
What statistical method can be used to compare the means?
Dependent
paired t-test
If subjects are treated in different ways e.g. different hip implant, are the results dependent or independent of eachother?
independent
What statistical method can be used to compare the means in independent data sets?
independent sample t-test
in what situation is a paired t-test used?
dependent data sets
in what situation is an independent sample t-test applied?
independent data sets
If the data is not continual, can a t-test be applied?
no
