class 13

Question 1

purpose of statistics in research

Answer 1

-describe
-explain
-make predictions
-examine causality
-generalize to entire population
-explore and test theories

Question 2

clinical use of statistics

Answer 2

-analyzing research done by nursing staff
-reading or critiquing published reserach
-examining outcomes of nursing practice
-examine administrative data
-demonstrate a problem or need
-developing administrative reports

Question 3

what is the purpose of descriptive stats?

Answer 3

describe and summarize data (e.g. averages, frequencies, etc)

Question 4

what is the purpose of inferential stats?

Answer 4

test hypothesis and/or answer questions, objectives
-allow inference from a sample to a population

Question 5

4 types of descriptive stats used to summarize data

Answer 5

-frequency distribution
-central tendency
-variability
-bivariate descriptive statistics

Question 6

what is a frequency distribution?

Answer 6

-data values arranged from highest to lowest, with count of occurrences of each value
-allows to easily see highest and lowest values, and where data are clustered
data can be:
-symmetric vs skewed
-grouped vs ungrouped

Question 7

normal frequency distribution

Answer 7

middle value is the mean and distributions go up or down following the standard deviation (+1,+2,+3 etc)
-the curve is even on both sides of the mean

Question 8

kurotsis in frequency distributions

Answer 8

the degree to which the data clusters around the peak or the tails of the distribution

Question 9

leptokurtic frequency distribution

Answer 9

data clusters around the mean (large peak with steep curve)

Question 10

platykurtic frequency distribution

Answer 10

data is distributed evenly across the graph (curve has very little peak and low degree of curve)

Question 11

grouped frequency distribution

Answer 11

data collected is in “groups” i.e. 10-20,21-30, 31-40 etc

Question 12

positive skewed frequency distribution

Answer 12

the data is “ more negative” aka the mean is a lower number than the median
peak is close to the y-axis

Question 13

negative skewed frequency distribution

Answer 13

data is “more positive” aka mean is a higher number than the median
peak is further from the y-axis

Question 14

ungrouped data in frequency distributions

Answer 14

data collected is only 1 number not a range for each answer
i.e. how many kids do you have 1,2,3,4

Question 15

what is central tendency

Answer 15

indicate what is “typical” (average) of the data
-three indexes: -mean, median, and mode

Question 16

what is mode

Answer 16

it is a part of central tendency
the value or score that occurs the most frequently
i.e.1846444857 mode is 4

Question 17

what is median

Answer 17

it is a part of central tendency
the point that divides the scores in half (i.e. marks 50th percentile)

Question 18

what is mean

Answer 18

it is a part of central tendency
sum of values divided by number of values being summed

Question 19

what is variability

Answer 19

-measures of dispersion: the way data are spread within a set
2 common types: -range -standard deviation

Question 20

what is range

Answer 20

it is a part of variability
difference between highest & lowest scores in a data set
-calculated by subtracting lowest score from the highest score

Question 21

what is standard deviation

Answer 21

it is a part of variability
-summarizes average amount of deviation from the mean
-calculated using every value in data set
-more stable and widely used than range to measure variability

Question 22

what are bivariate descriptive statistics

Answer 22

-describe relationships between two variables
-text lists various types:
-cross-tabulations
-correlations
-descriptions of risk

Question 23

what is correlation

Answer 23

it is a part of bivariate descriptive statistics
-to what extent are two varaibles related to one another
-described using correlation coefficients :-direction -intensity
-can be positive or negative, strong or weak

Question 24

what is a positive correlation?

Answer 24

values move in the same direction i.e. increase in temp correlates to an increase in ice cream sales

Question 25

what is a negative correlation

Answer 25

values move in opposite directions i.e. increase in AC sales correlates to decrease in sweating

Question 26

what is a correlation coefficient

Answer 26

measures strength of correlation between to variables
range from -1.00 to +1.00
-sign (- vs +) indicates direction
-absolute value (i.e. value regardless of sign) indicates intensity
-several types:
-pearson’s r
-spearman’s rho
-Kendall’s tau

Question 27

what is pearson’s r

Answer 27

-part of bivariate descriptive statistics correlation coefficients
-usd to measure relationships in interval or ratio-level data
-used when data are assumed to be normally distributed
-reported as r=x

Question 28

what is spearman’s rho

Answer 28

-part of bivariate descriptive statistics correlation coefficients
-range from -1-+1
-used to measure relationships in ordinal level data
-may be used when data are not normally distributed
-reported as p=x

Question 29

what is a risk estimate

Answer 29

-it is a part of bivariate descriptive statistics
-range from 0-infinity
-1=no relationship
-value <1=risk factor
-value >1 = protective factor
-several types: Odds ratio (OR) Relative risk (RR)

Question 30

what is odds ratio

Answer 30

-it is part of risk estimate
-used to measure the odds of having been exposed to a condition if having developed an outcome of interest
-E.g. taking a sample of women who have postpartum depression and calculating their likelihood of having smoked during pregnancy
-reported as OR=x

Question 31

what is relative risk ratio

Answer 31

-used to measure the odds of developing an outcome of interest after having been exposed to a condition
-reported as RR=x
-e.g. in a study of the risk of smoking on PPD, taking a sample of pregnant women then examining them 6m after delivery to see if they developed postpartum depression