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Pharmacy Biostatistics > The Statistical Inference and Hypothesis Testing > Flashcards

The Statistical Inference and Hypothesis Testing Flashcards

1
Q

What is Statistical Inference?

A

Process of analyzing data from a sample to infer the true values or true effects in the population

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2
Q

What are the two complementary approaches of statistical inference?

A

Hypothesis testing and Statistical estimation (confidence intervals)

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3
Q

What are the characteristics of Hypotheses?

A
  1. A declarative sentence
  2. Describes a relationship between two or more variables
  3. Testable by empirical means
  4. Provides an indirect method of statistical inference
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4
Q

What is the Null Hypothesis H0?

A

What the researches are attempting to nullify, main purpose is to disprove a proposed assumption

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5
Q

What is the Alternate Hypothesis HA?

A

What happens if the null hypothesis is not true, hypothesis that researches are attempting to prove

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6
Q

What are components of the hypothesis testing?

A

Method focus on testing the null hypothesis only and conclusions are made in terms of rejecting or failing to reject the null hypothesis?

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7
Q

Distribution under H0 has what?

A

Sample Mean under the null hypothesis, centered on population mean U0

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8
Q

Standard Deviation of the Population Mean is what?

A

Standard Error

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9
Q

What is the formula for Standard Error of the Mean SEm?

A

SEm = SD / (square root of n)

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10
Q

Distribution under HA has what?

A

Sample Mean under the alternative hypothesis, centered on population mean UA, assuming the expected effect or difference

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11
Q

What does SEm represent?

A

How close the means of repeated samples will come to the population mean, describes the dispersion of means

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12
Q

What is a Type 1 Error?

A

Reject the null when the null is true, false positive

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13
Q

What is a Type II Error?

A

Fail to reject the null when the null is false, false negative

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14
Q

How to find the probability of Type 1 error?

A

Confidence

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15
Q

How to calculate Confidence?

A

1-a

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16
Q

How to find probability of Type 2 Error?

A

Power

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17
Q

How to calculate Power?

A

1-B

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18
Q

Define Power

A

Power 1-B is the probability of conclusion there is a difference when one actually exists (HA is true), you want statistical power in a study

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19
Q

What does the Z-Score show?

A

How many standard deviations away from the population mean we are

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20
Q

What is Probability (p)?

A

The probability of observing the sample data if the null hypothesis is true

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21
Q

What Apriori Alpha (a) level?

A

Specified in advance the critical value usually 0.05

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22
Q

Compare p to a allows you to reject or accept the H0

A

p less than a = reject
p greater than a = accept

23
Q

What are the types of hypothesis testing?

A

Non-Directional and Directional

24
Q

Non Directional Tests are?

A

Two-tailed, look in both pos and neg directions
alpha a is cut into two areas, one at each tail to look a pos/neg critical values

25
Q

Directional Tests are?

A

One-tailed, look in only one direction
Test of superiority and non-inferiority

26
Q

What is the formula to test the difference?

A

H0 = u1 - u2 = 0
the test is non-directional since the direction of the difference is not specified

27
Q

Research questions are framed as directional but..

A

tested using a non-directional test

28
Q

Rejecting the null says that there is a what?

A

Difference

29
Q

Failing to reject the null says that is what?

A

Insufficient evidence to conclude there is a difference

30
Q

What is testing for Equivalence?

A

Tests whether two quantities are within an acceptable range of each other

31
Q

Equivalence H0 = mean 1 - mean 2 =

A

greater than or equal to 10%

32
Q

Equivalence HA = mean 1 - mean 2 =

A

less than 10%

33
Q

What does rejecting the null say in testing for equivalence?

A

The that two are equivalent aka HA is less than 10%

34
Q

What is testing for Superiority?

A

Tests whether one quantity is greater than or less than the other

35
Q

Superiority H0 =

A

u1 - u2 < 0

36
Q

Superiority HA =

A

u1 - u2 > 0

37
Q

What does rejecting the null say in testing for superiority?

A

That one group is greater than than the other

38
Q

What is testing for Non-Inferiority?

A

Tests whether one quantity is no worse than a second quantity

39
Q

Non-Inferiority H0 =

A

Mean 1 - Mean 2 > Confidence Interval

40
Q

Non-Inferiority HA =

A

Mean 1 - Mean 2 < Confidence Interval

41
Q

What does rejecting the null say in testing for non-inferiority?

A

Says that one group is non-inferior to the other on the variable of interest

42
Q

How is non-inferiority different from equivalence?

A

Similar to equivalence but WITHOUT the absolute value because the test is directional

43
Q

What are the steps in Traditional Approach to performing hypothesis tests?

A
  1. Convert the research question into appropriate null and alternate hypothesis
  2. Select the appropriate statistical test
  3. Select the desired significance level and the appropriate critical value for the statistical test
  4. Calculate the test statistic
  5. Compare the test statistic to the critical value and draw conclusions
44
Q

How do you calculate Degrees of Freedom?

A

Sample Size - Number of Groups

45
Q

How do you calculate the Significance Level?

A

a / (number of groups)

46
Q

How do you calculate the Critical Value?

A

Use degrees of freedom and the significance level, Planas said she would provide it

47
Q

How to calculate the test statistic?

A

Planas said it would be provided ONLY on Exam 1

48
Q

If the test statistic is greater than the critical value what does that mean?

A

You reject the null hypothesis meaning HA is true

49
Q

The probability number found is the change of finding a result of this magnitude

A

Planas said it would be provided ONLY on Exam 1

50
Q

You want the p value to be less than alpha

A

Because you want the p value to be less than the alpha 0.05 to reject the null hypothesis

51
Q

What does Statistically Significant mean?

A

Null hypothesis is reject after statistical analysis

52
Q

What does Clinical Significance mean?

A

Whether the findings are clinically or practically meaningful

53
Q

Does statistical significance prompt use of new medication?

A

No cause it does not mean it is clinically significant

Pharmacy Biostatistics (17 decks)

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