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EBP (starting with Exam 2 content) > Ch 14 > Flashcards

Ch 14 Flashcards

1
Q

statistical analysis: what is a nominal measure?

A

A nominal measure is the lowest level and involves using numbers to designate attributes. In other words, things are indicated by a numeric value, but that numeric value can’t be used mathematically. Eye color is an example. Brown can be 1, Blue can be 2, Green can be 3, etc.

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2
Q

statistical analysis: what is an ordinal measurement?

A

Ordinal measurements rank people based on an attribute such as ADLs. The text example has a 4 being independent and 1 being completely dependent. The number relates to the rating of an attribute.

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3
Q

statistical analysis: how do interval measurements rank people?

A

Interval measurements rank people on attributes with a number that clearly specifies a distance between the two. An IQ test is an example of this.

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4
Q

statistical analysis: what measurement is the highest level?

A

ratio

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5
Q

stat anal: explain ratio measurements

A

Ratio measurements are the highest level, and the numbers included are able to have a meaningful zero. They are ratio measures because two values that can be accurately described by their ratio. Weight is an example. The text provides the example of saying a 200 pound person is clearly twice the weight of a 100 pound person.

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6
Q

stat anal: what are continuous variables?

A

Continuous variables are variables with interval and ratio measurements.

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7
Q

___statistics are used to synthesize and describe data.

A

Descriptive

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8
Q

Parameters are ___

A

calculated values such as averages and percentages.

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9
Q

Statistic is ___

A

Statistic is a descriptive index from a sample.

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10
Q

what is a frequency distribution?

A

A frequency distribution takes a list of values and organizes it lowest to highest and includes a count. For instance, if there were ten values and 5 of them were 80, it would list 80 once and put a count of 5 and a percentage of 50%. Table 14.2 provides a visual to demonstrate this.

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11
Q

Symmetric distributions are ones where ___

A

Symmetric distributions are ones where if the graph is folded in half the two halves would be superimposed.

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12
Q

In a skewed distribution the majority of the data ___

A

peaks to one side.

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13
Q

A normal distribution is ___

A

a bell-shaped curve which has a lower peak than other types of distributions. Human attributes occur as bell-shaped curves such as height and intelligence.

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14
Q

central tendency includes…

A

Central tendency includes methods to determine a central value for a set of numbers.

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15
Q

the mode is…

A

The mode is the number that occurs most frequently in a distribution.

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16
Q

the median is…

A

The median is the point in a distribution that divides scores in half.

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17
Q

the mean is..

A

The mean equals the sum of all values divided by the number of participants.

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18
Q

stat anal: what is variability?

A

Measures of central tendency can be the same for two different sets of distributions. This is known as variability.

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19
Q

what is the range?

A

The range is the highest minus the lowest score in a distribution.

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20
Q

what is standard deviation?

A

The standard deviation is a variability index calculated based on every value in a distribution. It is the average amount of deviation of values from the mean. The lower the standard deviation the more homogenous the distribution.

The actual value of a standard deviation is unique for each study

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21
Q

describe standard dev. in a normal distribution (percentages within one/two SD)

A

For a normal distribution or bell-shaped curve, 68% of values will be within one standard deviation of the mean and 95% of values will be within 2 standard deviations of the mean.

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22
Q

when can a crosstabs crosstable be used?

A

If a frequency distribution is based on two variables instead of one a crosstabs crosstable can be used to depict the data. Table 14-3 depicts this. Gender across the top creates tabs for women and men. Smoking status and its identifiers are on the left.

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23
Q

what are correlations?

A

Correlations are methods to describe relationships between two variables.

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24
Q

describe the correlation coefficient

A

The correlation coefficient is the intensity and direction of the relationship between two variables. Correlation coefficients range from -1.0 to 0 to 1.0. A positive 1.0 would mean a perfect relationship. A positive relationship represents values between 0 and +1.0. Negative relationships represent values between -1.0 to 0.

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25
Q

The most widely used correlation statistic is ___

A

The most widely used correlation statistic is Pearson’s r (the product-moment correlation coefficient).

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26
Q

___ is a correlation coefficient calculated for values on an ordinal scale.

A

Spearman’s rho is a correlation coefficient calculated for values on an ordinal scale.

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27
Q

A correlation matrix displays ___

A

A correlation matrix displays correlation coefficients in tables displaying rows and columns.

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28
Q

what is absolute risk?

A

Absolute risk is the proportion of people who experienced an undesirable outcome in each group. For example, one group of people had education on falls and are the experimental group, and the control group did not have education on falls. 10% of individuals in the experimental group had falls, while 30% of the individuals had falls in the control group. The absolute risk would be 0.10 for the intervention group and 0.30 for the control group.

29
Q

what is absolute risk reduction?

A

The Absolute risk reduction is a comparison of the two risks.
Subtracting the AR from the exposed from the AR of the control group. For the case before .30 - .10 = .20 or 20%. This suggests that 20% more of the control group would not fallen with the intervention

30
Q

what is odds ratio?

A

Odds ratio is the ratio of two odds. The odds are of an undesirable effect. For the intervention group it would be the number who had the adverse effect divided by those that did not. In the above example 70 / 30 = 2.33. For the control group it would be 90 / 10 = 9.00. 2.33 / 9 = 0.259 which is the odds ratio. This means the odds of falling with education is 25%, and the odds of falling without education is 400% more likely.

31
Q

what does “the number needed to treat” estimate?

A

The number needed to treat estimates how many people need to receive an intervention to prevent one undesirable outcome. 1 divided by the absolute risk reduction calculates this. 1 / .20 = 5. Five people would need to receive education on falls.

32
Q

Inferential statistics use ___ to test research hypotheses with data.

A

Inferential statistics use the law of probability to test research hypotheses with data.

33
Q

A larger sample size helps reduce ___

A

the chance of outlying data.

34
Q

Standard Error of the Mean is ___

A

the standard deviation of the mean of a sample. The higher the number the more error associated with the sample selected. In other words, a lower SEM reflects a more appropriate sample size.

35
Q

Parameter estimation is used to ___

A

estimate a population parameter such as the mean.

36
Q

A confidence interval relates to ___

A

the probability of being right. A confidence interval of 95% and 99% is the goal for most researchers.

37
Q

Hypothesis testing uses ___ to determine if the hypothesis is supported or rejected.

A

Hypothesis testing uses objective criteria to determine if the hypothesis is supported or rejected.

38
Q

A null hypothesis is when __

A

there is no relationship between the independent variable and dependent variable.

39
Q

A type I error is ___

A

rejecting the null hypothesis that is in fact true.

40
Q

Type II error ___

A

assumes the null hypothesis is true when in fact the independent variable did have an effect.

41
Q

The level of significance is indicated by the ___

A

alpha or a designation.

42
Q

how to calculate the level of significance

A

The level of significance or alpha is the confidence interval subtracted by 1.0. We wanted a CI of 95% or 99%. Therefore, we want alpha values of .05 or .01. In other words, alpha of 0.05 means a type I error will occur 5% of the time.

43
Q

The chance of having a type II error is reduced by ….

A

increasing the sample size.

44
Q

A ___ is calculated to determine the chance of a type II error. What’s the goal?

A

A power analysis is calculated to determine the chance of a type II error. A goal is a power of at least 0.80, which means there is .20 or 20% risk of a type II error.

45
Q

Statistical significance means ___

A

the results are not likely to be due to chance. A nonsignificant result means that the results could be due to chance.

46
Q

Statistical significance is values that fall within ___. Confidence intervals of 95% or greater represent statistically significant values

A

Statistical significance is values that fall within 2 standard deviations of the mean. Confidence intervals of 95% or greater represent statistically significant values

47
Q

what is a parametric test

A

A parametric test for testing differences in two group means is called a t-test. A t value will be calculated but the individual value is not important. A p value will be calculated and that is what determines if the results are significant. A p value of < 0.05 indicates statistical significance. Independent t-tests are appropriate for two different groups of people and a paired t-test is used when one group is tested at two different points in time

48
Q

difference between independent and paired t-tests

A

Independent t-tests are appropriate for two different groups of people and a paired t-test is used when one group is tested at two different points in time.

49
Q

Analysis of variance or ANOVA is used to ___

What is the F value?

A

Analysis of variance or ANOVA is used to test mean group differences of three or more groups. ANOVA calculates a F value which varies for each study, but like the t-test will give us a p value. ANOVA will show the interventions are effective or supported with a p value of < 0.05.

50
Q

A chi-squared test focuses on …

A

A chi-squared test focuses on the difference in proportion. If blood sugars were controlled in 60% of patients with a diabetes educational intervention versus 40% of patients without, is the 20% real? Just like the other tests, the value of chi-squared varies for test to test. The p value of <0.05 would determine if it is statistically significant.

51
Q

Multiple Regression measures ___

What is the statistic and what does it measure?

A

Multiple Regression measures several independent variables. Independent variables are called predictor variables in multiple regression. A statistic called a multiple correlation coefficient is calculated and known as R. R varies from 0.0 to 1.00. R squared gives a percentage of how influential the predictors were. A higher R squared value means it is more likely the predictors accounted for the variation.

52
Q

ANCOVA is a …

A

ANCOVA is a combination of ANOVA and multiple regression. ANCOVA is good when there is not control through randomization. ANCOVA attempts to control covariates of confounding variables.

53
Q

Logistic Regression analyzes …

What does it yield?

A

Logistic Regression analyzes the relationships between multiple independent variables. Logistic Regression will yield an odds ratio called a OR for each independent variable as well as a confidence interval.

54
Q

Intraclass correlation coefficient is used for…

A

Intraclass correlation coefficient is used for test-retest reliability and ranges from 0.00 to 1.00. A score closer to 1 means stronger reliability.

55
Q

Cohen’s kappa is used for…

A

Cohen’s kappa is used for dichotomous classifications. Helpful to determine if two individuals would rate something similarly.

56
Q

Coefficient alpha or Cronbach’s alpha is used to …

A

Coefficient alpha or Cronbach’s alpha is used to measure how often components of a multicomponent tool measure the same attribute.

57
Q

Content validity determines if …

A

Content validity determines if the content of the items adequately reflects the construct of interest. Experts meet to rate each item to determine a content validity index. 0.90 or higher indicates good content validity.

58
Q

Criterion validity concerns the …

A

Criterion validity concerns the extent to which scores on a measure are consistent with a gold standard criterion. Two terms fall under this type of validity.

59
Q

Sensitivity vs specificity

A

Sensitivity is the ability of a measure to correctly screen or diagnose a condition. Specificity is the measure’s ability to correctly identify non-cases or screen out those without the condition. Think about a diagnostic test such as a flu swab. A specific flu swab would not be positive for strep or other conditions. A sensitive flu swab would be positive for the flu most of the time. What if a flu swab always caught the flu, but also would show positive for strep? It would still be sensitive, but it would have a lower specificity. You can have the reverse too. A swab that only detected flu would be highly specific. A swab that only successfully detected half the cases of flu would have low sensitivity but still be highly specific.

60
Q

Construct validity concerns …

A

Construct validity concerns the extent to which a measure is truly measuring the target construct. It uses various procedures such as Pearson’s r value, or an independent group t-test.

61
Q 
Which level of measurement applies to IQ scores?
A) Nominal
B) Ordinal
C) Interval
D) Ratio
A

Answer: C, interval.

IQ scores are representative of an interval measurement.

62
Q 
Which type of distribution is represented by a bell-curve?
A) Frequency
B) Skewed
C) Symmetric
D) Normal
A

Answer: D, normal.

A bell-curve is typical for a normal distribution. This includes parameters such as height and intelligence

63
Q 
Which type of distribution is represented by a bell-curve?
A) Frequency
B) Skewed
C) Symmetric
D) Normal
A

Answer: D, normal.

A bell-curve is typical for a normal distribution. This includes parameters such as height and intelligence

64
Q 
What is the sum of all variables divided by the number of participants?
A) Mean
B) Mode
C) Range
D) Median
A

Answer A: mean

Mean, median, and mode are three measures of central tendency. The mean is the average which adds all variables together and divides them by the number of participants. Range is the highest value minus the lowest value. It does not measure central tendency.

65
Q 
To be statistically significant what standard deviation value is needed with a normal distribution?
A) < 1
B) within 2
C) 3-4
D) > 5
A

Answer: B, within 2.

For a bell-shaped curve or a normal distribution, a 95% confidence interval is associated with two standard deviations.

66
Q 
Which value is best at establishing statistical significance?
A) p
B) Chi-squared
C) t
D) ANOVA
A

Answer A: p

Each type of statistical test will calculate a value for a research study; however, it will also calculate a p value. It is uniform through testing to designate a p value of < 0.05 as meaning it is statistically significant

67
Q 
Which values are specific for calculating reliability? (Select all that apply).
A) Cohen’s kappa
B) Specificity
C) Cronbach’s alpha
D) Intraclass correlation coefficient
A

Answer: A, C, and D, Cohen’s kappa, Cronbach’s alpha, and intraclass correlation coefficient.

Specificity is a term that applies to validity.

68
Q 
A test for strep throat has been developed.  The test shows positive for every case of strep throat, but also shows positive for influenza.  What is the best way to classify this test?
A) Highly specific and highly sensitive
B) Highly specific and low sensitivity
C) Low specificity and highly sensitive
D) Low specificity and low sensitivity
A

Answer: C, low specificity and highly sensitive.

Since the test sometimes shows positive for influenza it would not be highly specific. Since the test shows positive for every case of strep throat it is highly sensitive.

EBP (starting with Exam 2 content) (10 decks)

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