BioStats Module 1

Question 1

What is the difference between descriptive and inferential statistics

Answer 1

Descriptive - displays data so that it can be organized, summarized, or described allowing for trending

Inferential - tests a sample to see if generalizations can be made about population. You can infer something about a population based on sample

Question 2

Independent Variable

Answer 2

predictor variable - Which variable are you saying will make a change? the variable that is manipulated by the investigator.
educational tool used on two groups of people to see if skills increase.
educational tool = independent variable

Question 3

Dependent variable

Answer 3

The variable that depends on something - outcome variable - what is going to change? affected by the independent variable which variable shows the outcome of the experiment

2 groups educational tool used to increase skill level

skill level it the dependent variable

Question 4

Discrete Variables and discrete dichotomous

Answer 4

Can be counted like kids or heart rate
cannot be 0.5
Dichotomous - only two choices like sex

Question 5

continuous variables

Answer 5

Can be measured like height and weight can get more precise

based on precision of measurement tool

Question 6

What are the 4 levels of measurement

Answer 6

Nominal - qualitative
ordinal - qualitative
interval - quantitative
ratio - quantitative

Question 7

Nominal variable data

Answer 7

Qualitative - used to label variables without providing any quantitative value. cannot be ordered or measured . You cannot order or measured in a meaningful way
named categories, yes or no, race
preferred mode of transportation (car, bus, train, bicycle, tram, etc.)

Question 8

Ordinal data

Answer 8

Qualitative - categorical data with innate or natural order to them and the distances between them are not known.

good, fair, poor

neither agree nor disagree, agree, strongly agree

Question 9

Interval data

Answer 9

quantitative - data which is measured along a scale in which each point is placed at an equal distance.

temperature, pH, SAT score, credit score

Question 10

Ratio data

Answer 10

quantitative meaningful zero and ratio or equal proportion is present. ie INCOME you can make zero dollars and someone making 100k is twice as much as someone making 50k
uses same statistical tests as interval

Question 11

Variables are not innately nominal, ordinal, interval or ratio. What does this mean?

Answer 11

it depends on how the data is measured in the study

Weight - could be interval because you detail precise
could also be ordinal if you check boxes for a range of weights 80-120 kg check

Question 12

Bar Chart

Answer 12

Most appropriate for variables measured at nominal and ordinal level that are discrete NOT continuous
bars are proportional to the number of cases
easy to look at data SPACE between bars

Question 13

Histogram

Answer 13

similar to bar chart but the bars touch each other and is used to show continuous interval or ratio data

organizes data in several intervals instead of each data point receiving its own bar. Allows you to understand the general data distribution better

Question 14

Stem and leaf plots

Answer 14

look like bar chart on its side 
column on left is stem
on right is leaf 
1 I 9
2 I 2 5 6 7 8 9
3 I 0 4 6 7 
4 I 2 3 4 6 8 8 9
5 I 2 3 4 4 5
6 I 2

shows individual data points and shows data distribution

Question 15

Frequency Table

Question 16

Graphing Frequency table

Answer 16

displays values, frequency, valid percent, and cumulative percent

Valid percent is important if you have missing data

Question 17

Graphing Frequency distribution

terms for curves

Answer 17

Leptokurtic (thin)
Mesokurtic (normal)
Platykurtic (flat)

Question 18

positive skew

Answer 18

Tail slopes to the right

Question 19

negative skew

Answer 19

Tail slopes to the left

Question 20

Boxplot (Box and whicker plot)

Answer 20

shows median, mean, 25th and 75th percentile and any outliers

Question 21

What is central tendency

Answer 21

describes where typical data set would be - mean, median or mode

Question 22

Mean

Answer 22

average
cannot be done for nominal data MUST be interval or ratio level data
CANNOT be categorical data like some college

Question 23

Median

Answer 23

ordinal, interval or ratio
middle score where half is smaller and half is larger
could be used for not good, good, very good because to is ORDERED

Question 24

Mode

Answer 24

any type of data can be used
mode is the most frequently occurring data

1, 3,4,6,7,7
mode is 7 as it occurs more frequently than others

Question 25

Dispersion

Answer 25

standard deviation and variance

range, interquartile range

Question 26

Standard deviation small

Answer 26

close to mean or median more clustered or closer together

Question 27

variance

Answer 27

square root of the standard deviation
used with data sets that are not equal

40 RN3s and 125 RN1s

Question 28

Range

Answer 28

max - min = range

smaller = closer together 
larger = further spread apart

Question 29

Interquartile range

Answer 29

gives middle 25th percent and 75th percent