Chapter 14: Biostatistics Flashcards
This kind of data has a logical order with values that continuously increase or decrease by the same amount (e.g., a HR of 120 BPM is twice as fast as a HR of 60 BPM)?
Continuous data
What is the difference between interval and ratio data?
Interval data has no meaningful zero (zero does not equal none) and ratio data has a meaningful zero (zero equals none)
What are the two types of discrete/categorical data?
Nominal and ordinal data
Which type of categorical data sorts subjects into arbitrary categories (names), such as male and female (0=male, 1=female or 0=female, 1=male)
Nominal data
Which type of categorical data is ranked and has a logical order, such as a pain scale?
Ordinal data
The mean is preferred for ____ data that is ____ distributed
Continuous; normally
The median is preferred for ____ data or ____ data that is skewed
Ordinal; continuous
The mode is preferred for ____ data
Nominal
Indicates how spread out the data is and to what degree the data is dispersed away from the mean
Standard deviation
Data that is highly dispersed has a ___ standard deviation
larger
Large sample sets of continuous data tend to form a ____ distribution
Gaussian or normal “bell-shaped”
When the distribution of data is normal, the curve is ____
Symmetrical (half of the values are on the left side and half of the values are on the right side)
When the distribution of data is normal, the mean, median and mode are ____ (the same or different)
The same
When the distribution of data is normal, __% of values fall within 1 SD of the mean and __% of the values fall within 2 SD of the mean
68%; 95%
Skewed distributions where 68% of the values do not fall within 1 SD of the mean and the mean, median and mode are not the same value usually occurs when the sample size is ___ and/or there are ____ in the data
Small; outliers
When there are a small number of values, an outlier has a ____ (small or large) impact on the mean and the data becomes skewed
Large
The distortion of the central tendency caused by outliers is ____ (increased or decreased) by collecting more values
Decreased
When there are more low values in a data set and the outliers are the high values, data is skewed to the ____ (left or right)
Right (positive skew)
When there are more high values in a data set and the outliers are the low values, data is skewed to the ____ (left or right)
Left (negative skew)
_____ states that there is no statistically significant difference between groups & is what the researcher hopes to disprove or reject
The null hypothesis
______ is what the researcher tries to prove or accept
The alternate hypothesis
When investigators design a study, they select a maximum permissible error margin, called ____, which is the threshold for rejecting the null hypothesis
Alpha
In medical research, alpha is usually set at ___
5% or 0.05
If the alpha is set at 0.05 and the p-value is less than alpha (p <0.05), is the null hypothesis rejected or accepted? Is the result termed statistically significant or insignificant
Rejected; statistically significant