More hypothesis testing °❀⋆.ೃ࿔*:・ Flashcards

1
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A
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2
Q

What is the null hypothesis (H0)?

A

Responses are equivalent to random guesses

H0 (pronounced H-naught) represents the status-quo in hypothesis testing.

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3
Q

What is the alternative hypothesis (HA)?

A

People have knowledge that helps them do better than random guessing or false knowledge leading to worse performance

HA (pronounced H-A) represents a new or stronger perspective.

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4
Q

What percentage of correct answers would you expect from random guessing with three options?

A

33.3333%

This is derived from having one correct answer out of three options.

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5
Q

What is the basic framework of a hypothesis test?

A

It involves the null hypothesis (H0) and the alternative hypothesis (HA) to determine if there is evidence against H0

The framework starts with skepticism towards the alternative hypothesis.

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6
Q

True or False: Failing to reject the null hypothesis means it is true.

A

False

Failing to reject H0 means there isn’t strong evidence against it, but does not confirm its truth.

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7
Q

What does it mean to fail to reject the null hypothesis?

A

It means the evidence for the alternative hypothesis is weak

It does not imply that the null hypothesis is accepted as true.

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8
Q

What is a key part of the scientific method in hypothesis testing?

A

Starting from the position of a skeptic

The null hypothesis is considered the real one until strong evidence suggests otherwise.

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9
Q

What is the purpose of hypothesis testing?

A

To determine if there is enough evidence to reject the null hypothesis

Hypothesis testing helps in making conclusions about population parameters.

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10
Q

What is the notation for the population parameter in hypothesis testing?

A

It is written as ‘p’

This notation represents the proportion of the population that meets the criteria of the hypothesis.

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11
Q

What does a p-value indicate?

A

The strength of evidence against the null hypothesis

A lower p-value suggests stronger evidence against H0.

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12
Q

What is a confidence interval?

A

A range of values that estimates the population parameter with a certain level of confidence

It helps in understanding the variability and uncertainty in sample estimates.

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13
Q

What is the critical value for a 95% confidence interval based on the z-score?

A

It is determined through statistical tables

The critical value is used to calculate the margin of error for the confidence interval.

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14
Q

What is the point estimate in hypothesis testing?

A

It is the sample proportion (p-hat)

Point estimate serves as a best guess for the population parameter based on sample data.

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15
Q

Fill in the blank: The jury considers whether the evidence is so convincing that there is no reasonable doubt regarding the person’s _______.

A

guilt

This analogy illustrates hypothesis testing in a legal context.

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16
Q

What does it mean if the null value falls within the range of plausible values from the confidence interval?

A

We cannot say the null value is implausible

This indicates insufficient evidence to reject the null hypothesis.

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17
Q

What is the sample size in the example about college-educated adults answering the vaccination question?

A

50

This is the number of respondents considered in the hypothesis testing example.

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18
Q

What is p-hat in hypothesis testing?

A

The sample proportion of respondents who answered correctly

This helps in estimating the population parameter for hypothesis testing.

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19
Q

What is the significance of the central limit theorem in hypothesis testing?

A

It allows for the approximation of the sampling distribution of the sample mean

This theorem is crucial for ensuring the validity of hypothesis tests when sample sizes are large.

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20
Q

What is the standard error often computed differently in the context of?

A

Hypothesis test for a proportion

The standard error can vary depending on the test being conducted.

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21
Q

What conclusion can we draw if the data do not provide sufficient evidence to reject H0?

A

Fail to reject the null hypothesis H0

This implies that we cannot confirm a difference from random guessing.

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22
Q

Why can we not conclude that the null hypothesis is correct?

A

Failing to reject H0 does not mean it is true

There may be an undetected difference due to sample size limitations.

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23
Q

What condition does a small sample size fail to meet in the context of hypothesis testing?

A

Success-failure condition of the central limit theorem

This condition is crucial for the validity of hypothesis testing.

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24
Q

What is the null hypothesis (H0) in hypothesis testing?

A

Represents the status quo

It is the hypothesis that we assume to be true until evidence suggests otherwise.

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25
What is the alternative hypothesis (HA) in hypothesis testing?
Represents the research question being tested ## Footnote It is what we are trying to find evidence for.
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What do we conclude if there is strong evidence for the alternative hypothesis?
Reject the null hypothesis ## Footnote This indicates that we find statistically significant evidence in favor of the alternative.
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What is the purpose of calculating the p-value in hypothesis testing?
Quantifying the strength of evidence against the null hypothesis ## Footnote The p-value helps determine whether the null hypothesis can be rejected.
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What is a Type 1 Error in hypothesis testing?
False positive: rejecting H0 when it is actually true ## Footnote This error leads to incorrect conclusions about the presence of an effect.
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What is a Type 2 Error in hypothesis testing?
False negative: failing to reject H0 when HA is true ## Footnote This error results in missing a true effect.
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How can we reduce the Type 1 Error rate in courts?
Raise the standard for conviction ## Footnote This could lead to more Type 2 Errors as it becomes harder to convict the guilty.
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What happens when we reduce the Type 2 Error rate?
We may increase the Type 1 Error rate ## Footnote This reflects the trade-off between false positives and false negatives.
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What is the rule of thumb for rejecting the null hypothesis?
Do not reject H0 unless we have strong evidence ## Footnote Strong evidence typically means a low p-value.
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What is the desired false positive rate in hypothesis testing?
5% ## Footnote This corresponds to a significance level (α) of 0.05.
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What is the significance level in hypothesis testing?
The probability of incorrectly rejecting H0 ## Footnote It is denoted by α and is set based on the context of the test.
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What does a 95% confidence interval indicate in hypothesis testing?
Type 1 Error occurs about 5% of the time ## Footnote This is when the sample's estimate is significantly different from the population parameter.
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What does using a 99% confidence interval imply?
α = 0.01 ## Footnote More stringent criteria are used to avoid false positives.
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What does using a 90% confidence interval imply?
α = 0.1 ## Footnote This is used when avoiding false negatives is prioritized.
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What is the Central Limit Theorem?
Means from samples will be approximately normal in distribution as sample size increases ## Footnote This theorem underlies many statistical methods.
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What is the relationship between sample proportions and population proportions?
Sample proportions will be nearly normally distributed with mean equal to the population proportion p ## Footnote This holds true as sample sizes become large.
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What does the Central Limit Theorem state about the sampling distribution as sample size increases?
The sampling distribution gets more normally shaped ## Footnote This is a key concept in statistics.
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What is the mean of sample proportions according to the Central Limit Theorem?
Mean equal to the population proportion, p
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What is the standard error for sample proportions?
Standard error equal to the formula derived from the population proportion
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What is the first condition of the Central Limit Theorem (CLT)?
Sampled observations must be independent
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What is more likely to ensure independence in sampling?
Random sampling/assignment
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What is the maximum sample size in relation to the population for the CLT to hold?
Sample size n must be LESS than 10% of the population
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In the example provided, what was the sample size used to estimate pushback from the town?
n = 100 people
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What happens to standard error as sample size increases?
Standard error decreases
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What is the difference between p-value and effect size?
The p-value is different than the size of the effect
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What does a small p-value indicate in hypothesis testing?
Strong evidence against the null hypothesis
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What is the significance level (alpha) typically set at in hypothesis testing?
α = 0.05
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What is the null hypothesis (H0) in the example regarding coal usage?
There is no majority support or opposition to expanding coal usage
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What does statistically significant mean in the context of hypothesis testing?
The sample statistic is unusual enough relative to the null hypothesis to reject it
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What two statements are evaluated in a hypothesis test?
Two mutually exclusive statements about a population
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What is the success-failure condition in hypothesis testing?
Check if n*p and n*(1-p) are both greater than or equal to 10
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How do you calculate the p-value in hypothesis testing?
By evaluating the tail area under the null distribution
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What is the outcome if the p-value is less than the significance level?
Reject the null hypothesis
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What does a good p-value not necessarily imply?
The results are useful and interesting
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What is the null value used for in hypothesis testing?
The null value p0 is used for the proportion in calculations
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What does the term 'unusual enough' refer to in hypothesis testing?
How far the sample statistic is from the null hypothesis value
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What is the critical region in hypothesis testing?
The area in the tail of the distribution where we reject the null hypothesis
61
What does winning 65% of foosball games indicate about my skill level?
It suggests a proficiency in foosball, but further statistical analysis is needed to claim superiority with confidence.
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Can I claim I'm better at foosball with 99% confidence if I win 65% of 80 games?
Statistical tests are required to determine if the claim is valid.
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What are the hypotheses in the context of statistical testing?
Ho (null hypothesis) and Ha (alternative hypothesis).
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What is the significance level in hypothesis testing?
It is the threshold at which you determine whether to reject the null hypothesis.
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What is the p-value in hypothesis testing?
It indicates the probability of observing the data if the null hypothesis is true.
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If a federal loan program benefits a community if at least 30% of businesses qualify, what action is taken if only 28% qualify from a sample of 100?
Oppose the federal loan program based on the sample results.
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What was the outcome of the Pew Research Poll regarding payday loan regulations?
51% of 826 respondents supported increased regulation.
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What does p ≠ 0.50 indicate in the context of the payday loan borrowers' support?
It suggests that the majority either support or oppose the regulation.
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How is the standard error calculated in a one-proportion hypothesis test?
Using the null value, p0.
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What does the Z-score represent in hypothesis testing?
It is the test statistic computed from the point estimate.
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What is the significance of a p-value larger than 0.05?
It indicates weak evidence against the null hypothesis.
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What does a high p-value suggest about the null hypothesis?
Your data are likely compatible with a true null hypothesis.
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What is the relationship between p and p-hat?
Both are point estimates for a population proportion, but p-value is different.
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What defines statistical significance in hypothesis testing?
When the sample statistic is unusual enough relative to the null hypothesis.
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What are common alpha values used in hypothesis testing?
0.05 and 0.01.
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Does alpha always equal 0.05?
No, it can be adjusted based on the application.
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What should you consider when selecting a significance level?
The type of error you are more concerned about (false positives vs. false negatives).
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What happens if a false positive is especially costly?
Choose a smaller significance level (e.g., α = 0.01).
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What is a strategy to reduce the false negative rate?
Collect more data.
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What is the null hypothesis in the context of flawed hinges rate?
H0: p = 0.002.
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What is the alternative hypothesis regarding the rate of flawed hinges?
HA: p ≠ 0.002.
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What is the significance level that seems reasonable for the flawed hinges example?
0.05.
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What should the car company do if evidence suggests one supplier's parts are better?
Reject H0 and switch suppliers.
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What might be an appropriate significance level for choosing a supplier based on safety?
α = 0.10.
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What should a car company do when safety is involved and evidence is moderately strong?
Switch to the slightly more expensive manufacturer ## Footnote This decision is based on the rejection of the null hypothesis (H0)
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What is a slightly larger significance level that might be appropriate in safety-related decisions?
α = 0.10
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What is the significance level in hypothesis testing?
A threshold that determines how far out from the null hypothesis value we draw the line on the graph
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What are the common alpha values based on tradition?
* 0.05 * 0.01
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What must a researcher/analyst do regarding the significance level before conducting a test?
Select an alpha
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What is considered bad form in hypothesis testing?
Raising the significance level after analysis to find statistical significance
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What is the null hypothesis in the example regarding average energy cost?
The true population mean equals the hypothesized null mean (µ0 = 260)
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What does the alternative hypothesis state in the energy cost example?
The true population mean differs from the hypothesized null mean (µ0 ≠ 260)
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What is the critical region in statistics?
Shaded areas in a distribution where the sample mean falls under the null hypothesis
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What does a sample mean falling within the critical region indicate?
It is statistically significant at the α=0.05 level
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What does a P value represent?
The probability of obtaining an effect at least as extreme as the one in your sample data, assuming the truth of the null hypothesis
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What happens when a P value is less than or equal to the significance level?
Reject the null hypothesis
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What is the significance level that guards against false negatives?
α = 0.01
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What is the outcome when a sample mean does not fall within the critical region at α=0.01?
Fail to reject the null hypothesis
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What are the two types of errors in hypothesis testing?
* Type 1 Error: False positive * Type 2 Error: False negative
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What is the standard error in hypothesis testing?
Calculated based on the sampling distribution
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What is a test of group differences used for?
To determine if two groups' opinions or measurements differ in a larger population
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What statistical tests are used for group differences?
* T-test (2 groups) * ANOVA (more than 2 groups)
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What do tests of association/correlation examine?
The relationship between two numerical variables
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What does the correlation coefficient R indicate?
The strength and direction of a linear relationship between two variables
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What does R² represent in linear regression?
The proportion of variance for one variable that's explained by another variable
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What does ANOVA stand for?
Analysis of Variance
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What is the purpose of tests of association/correlation?
To determine the relationship between two numerical variables
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What does a correlation coefficient R indicate?
The strength and direction of a linear relationship between two variables
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What does R² represent in regression analysis?
The proportion of variance in the dependent variable that can be explained by the independent variable(s)
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What is the main goal of regression analyses?
To predict the value of a dependent variable based on independent variable(s)
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What is Ordinary Least Squares (OLS)?
A method for estimating the parameters in a linear regression model
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What is the purpose of testing group differences?
To determine if two groups' measurements are significantly different in the larger population
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Provide an example of a scenario where group differences might be tested.
Mental health outcome scores after new treatment
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In the context of regression, what does the term 'dependent variable' refer to?
The outcome variable that researchers are trying to predict
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What does the statement 'if they have eggs, get a dozen' illustrate in programming?
The importance of being explicit in instructions or commands
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Fill in the blank: Regression analyses are powerful tools that allow analysts to ______ outcomes of future observations.
anticipate
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What does CI95Zstar represent in statistical calculations?
The z-score for a 95% confidence interval
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What is the formula for calculating standard error (SE) for a class vaccination guess?
sqrt(0.33*0.67/12)
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True or False: The programmer returned home with 12 gallons of milk because of an implicit instruction.
True
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What does SEnew represent in the context of standard error calculations?
The standard error for a new estimate
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What statistical function is used to find the probability of a value in a normal distribution?
pnorm