unit 4: what is a sample?

subset of the population selected for study

Unit 1 : what is an outlier

a value that's far from the rest of the data

Unit 1: Which of the following is an example of a population in a statistical study?

all students in a school district

Unit 5: what's a probability model

is a description of a random process.

unit 7: what's a statistic

A numerical value that summarizes a characteristic of a sample

unit 7: what's the central limit theorem?

Sample means form a normal curve

unit 7: what's a sampling distribution?

Spread of a stat from many samples

unit 6: what's a random variable

takes on all possible number values for outcomes of a random event

unit 8: what's a point estimate?

A single value used to approximate a population parameter.

unit 7: what's a parameter

A numerical value that summarizes a characteristic of a population

Unit 1: what is the difference between categorical and quantitative data?

Categorical is labels; quantitative is numbers.

Difference between observed and predicted values

unit 2: what does standard deviation measure

how dispersed the data is in relation to the mean

unit 4: How do outliers effect the lsrl?

They can distort the slope and y-intercept.

unit 5: what's a simulation?

A process to model real-world scenarios using random sampling.

unit 3: what do scatter plots represent

the relationship between 2 quantitative variables

What conditions are needed for regression inference?

Linearity, independence, normality, equal variance

unit 5: what are mutually exclusive events in probability

Events that cannot happen at the same time.

unit 7: what's sampling variability?

Differences in population parameters over time

unit 10: Which of the following statements about the standard error is true?

It decreases as sample size increases

Unit 2: What is a z-score

the number of standard deviations a data point is from the mean

unit 9: What is a type II error?

Failing to reject null when it’s false

Unit 12: What kind of values make chi-square large?

Big differences between observed and expected

Unit 12:What is the chi-square formula

(Σ[observed-expected)²/expected])

unit 4: what's a categorical variable

A variable grouping data into categories

unit 3: what's an explanatory variable?

may explain or help us predict changes in a response variable

unit 3: what's a response variable

measures the outcome of a study, based on some type of input

unit 3: what does the correlation coefficient do?

explains the strength and direction of a linear relationship

unit 9: what is a p-value

Probability of getting your result or more extreme, assuming null is true

Unit 11: What is the alternative hypothesis?

Claim we are trying to find evidence for

unit 2: what do percentiles describe

a specific location within a distribution

Unit 6: What's a probability distribution

A list showing all outcomes and their probabilities.

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Stats final project

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Questions 70

Answers

1
unit 3: what is the line of best fit also called
Negative association
Failing to reject null when it’s false
least squares regression line
t-distribution
2
Unit 11:What is needed before running a t-test?
confidence interval
type 1 error
reject the null
randomness
3
unit 4: what is a sample?
a single data points from the population
the average value of a population
the entire group being studied
subset of the population selected for study
4
What does a residual plot show?
If linear model is appropriate
Variance of slope
Distribution of x-values
Mean of data
5
Unit 1 : what is an outlier
A value that occurs most frequently in a data set
a value that's far from the rest of the data
The last value in a data set
A data point that is exactly equal to the mean
6
Unit 1: Which of the following is an example of a population in a statistical study?
the height of one student
a random sample of 50 kids from a school
a survey result from 100 participants
all students in a school district
7
Unit 5: what's a probability model
A method to calculate averages in a data set.
A formula for determining sample sizes.
A tool to group data into specific categories.
is a description of a random process.
8
What does a small standard error of slope suggest?
High variability
Precise estimate of slope
Poor residuals
inaccurate model
9
unit 10: What distribution is used when population SD is unknown?
t-distribution
z- distribution
10
What does the intercept represent in regression?
Average of x
Spread of data
Predicted y when x = 0
Mean of residuals
11
unit 7: what's a statistic
A tool used only in probability theory
A numerical value that describes an entire population
A constant value that never changes
A numerical value that summarizes a characteristic of a sample
12
unit 7: what's the central limit theorem?
Samples must be large
Population mean always changes
All data is normal
Sample means form a normal curve
13
unit 7: what's a sampling distribution?
Way to collect samples
Spread of a stat from many samples
A list of all population data
Values in one sample
14
unit 6: what's a random variable
A variable that can take on any value in a data set.
A method to organize categorical data.
takes on all possible number values for outcomes of a random event
A variable that remains constant in an experiment.
15
unit 8: Does higher confidence level make a wider or narrower CI?
wider
narrower
16
unit 8: what's a point estimate?
A hypothetical value assumed for a population parameter.
The exact value of a population parameter.
A range of values used to estimate a population parameter.
A single value used to approximate a population parameter.
17
unit 7: what's a parameter
A method used to collect data
A value that describes a sample
A numerical value that summarizes a characteristic of a population
A variable that changes during an experiment
18
Unit 1: what is the difference between categorical and quantitative data?
Both are numbers but have different units.
Categorical is labels; quantitative is numbers.
Categorical is numbers; quantitative is labels.
Both are labels used for grouping.
19
What are residuals?
Points on the regression line
Outliers
Difference between observed and predicted values
Total deviation from mean
20
unit 2: what does standard deviation measure
the average value of a data set
how dispersed the data is in relation to the mean
the highest and lowest values in a data set
the total number of data points in a set
21
unit 8: The margin of error in a confidence interval depends on all the following factors except:
The standard deviation of the population or sample
The sample size
The size of the population
The level of confidence chosen (
22
unit 10: What does the t* value depend on?
Smaller sample, higher confidence level
Degrees of freedom
23
unit 4: How do outliers effect the lsrl?
They have no impact on the LSRL.
They can distort the slope and y-intercept.
They always increase the LSRL's accuracy.
They only affect predictions, not the LSRL itself.
24
unit 5: what's a simulation?
A technique to organize categorical data into groups.
A process to model real-world scenarios using random sampling.
A technique to organize categorical data into groups.
A way to calculate exact probabilities for an event.
25
Unit 13: What does the slope of a regression line represent
Standard error
Intercept
Change in y per unit x
Correlation
26
unit 3: what do scatter plots represent
the relationship between 2 quantitative variables
Infinite number of outcomes
To draw conclusions about a population from a sample
Simple random, stratified, or cluster sampling
27
Unit 12: What are 3 types of values make chi-square large?
lineriaty
independence
change in y per unit x
Goodness-of-fit, independence
28
What conditions are needed for regression inference?
Linearity, independence, normality, equal variance
All categories ≥ 5
Random and large sample
10% condition and random
29
unit 8: Does increasing sample size narrow the CI?
no
all the above
yes
it depends
30
unit 9: What is the null hypothesis?
Assumed true proportion
Strong evidence against null
31
unit 5: what are mutually exclusive events in probability
Events that have no effect on each other
Events that always occur together
Events that cannot happen at the same time.
Events that occur with equal probabilities.
32
unit 10: What happens to CI if sample size increases?
t-distribution
It becomes narrower
33
unit 7: what's sampling variability?
Errors that occur during data entry
Differences in sample statistics from one sample to another
Differences in population parameters over time
The method used to randomly select a population
34
unit 10: Which of the following statements about the standard error is true?
It equals the population standard deviation
It is constant regardless of sample size
It measures the variability of a single data point
It decreases as sample size increases
35
Unit 2: What is a z-score
the percentage of data points below a given value
the average value of a data set
the number of standard deviations a data point is from the mean
the raw score in a data set
36
unit 9: What is a type II error?
Failing to reject null when it’s false
Rejecting null when it's true
37
Unit 12: What kind of values make chi-square large?
Small differences between observed and expected
Big differences between observed and expected
categorical data
all should ne > 5
38
unit 11: what does a low p-value indicate in a test?
mean
Normal Distribution
Skewed
Strong evidence against null
39
unit 9: What does a small p-value mean?
Strong evidence against null
Failing to reject null when it’s false
40
Unit 12:What is the chi-square formula
categorical data
goodness-of-fit
comparing distribution
(Σ[observed-expected)²/expected])
41
What is homoscedasticity?
Skewed distribution
Zero residuals
High standard deviation
Equal spread of residuals
42
unit 4: what's a categorical variable
A variable always measured in percentages
A variable showing trends over time
A variable grouping data into categories
A variable with numerical values only.
43
Unit 12 What is the condition a for expected counts?
Each observed count must be greater than 5
Expected counts must be equal in all categories
The sum of all observed counts must equal the sum of expected counts
All should be ≥ 5
44
unit 3: what's an explanatory variable?
Correlation coefficient
may explain or help us predict changes in a response variable
45
unit 3: what's a response variable
Relationship between two quantitative variables
measures the outcome of a study, based on some type of input
46
unit 3: what does the correlation coefficient do?
The slope of the best-fit line through the data
The difference between observed and predicted values
explains the strength and direction of a linear relationship
The probability that the relationship between 2 variables is due to chance
47
unit 9: what is a p-value
Probability of getting your result or more extreme, assuming null is true
Assumed true proportion
48
Unit 11: What is the alternative hypothesis?
center of distribution
empirical rule
Claim we are trying to find evidence for
scatterplot
49
unit 2: what do percentiles describe
the spread of data from the mean
a specific location within a distribution
the average of all data points in a set
the frequency of a specific data poiny
50
Unit 11: what is the test statistic for one-sample t-test?
((x-u)[s/√n])
((x-p)[s/n)
(x-u)[n]
(( x̄ - μ) [s/√n])
51
Unit 6: What's a probability distribution
A measure of the most likely event to occur.
A graph showing the range of possible outcomes.
A list showing all outcomes and their probabilities.
A method to organize data into categories.
52
unit 5: what are independent events in probability
Events where one does not affect the other's likelihood.
Events that always have equal probabilities.
Events that cannot occur together.
Events that occur at the same time
53
unit 9: What is a type I error?
Failing to reject null when it’s false
Rejecting null when it's true
54
Unit 5: What is an event?
The total number of outcomes in a sample space.
The result of a single trial in an experiment.
A collection of possible outcomes of an experiment.
A method used to calculate probabilities.
55
unit 2: what do cumulative relative frequency graphs show?
the spread of data around the mean
the percentiles for individual data values
the total number of data points in a set
the frequency of each individual data points
56
Unit 12: when is a chi-square test used?
categorical data
scatterplot
independence
randomness
57
Unit 2: What is the shape of a normal distribution?
skewed to the right
uniform
skewed to the left
bell surve
58
unit 6: what's an expected value
The total number of outcomes in the sample space.
The outcome most likely to occur in an experiment.
The highest possible value in a probability distribution.
The average value of outcomes weighted by probabilities
59
Unit 6: what is variance
The average of all data points in a data set.
A measure of how data values spread around the mean.
A measure of how data values spread around the mean.
The square of the standard deviation.
60
What does extrapolating far beyond the data risk?
Increased accuracy
Lower residuals
Inaccurate predictions
Better model fit
61
unit 6: what's a continuous random variable?
A variable that takes on a fixed set of values.
all real number values within an interval and no gaps between values
A variable used to categorize data.
A variable with only whole-number values.
62
Unit 1: define mean
A number describing a population
Looking for difference in either direction
A number describing a population
the average of a set of numbers
63
unit 4: what is a population?
the entire group you're studying
A group of people living in the same geographic area
number of samples collected during an experiment
small group selected from a larger group for study
64
unit 10: What increases margin of error?
Smaller sample, higher confidence level
t-distribution
65
unit 8: What does "95% confidence" mean?
If many samples were taken, 95% of intervals would contain p
Strong evidence against null
66
Unit 1 : whats the shape of a symmetric distribution
uniform
skewed to the right
skewed to the left
bell-shaped
67
Unit 11: When do u use a two-nailed test?
looking for difference in either direction
significance level
p-value
looking for idifference in either direction
68
unit 8: what's a confidence interval?
Range of values likely to contain population parameter
The margin of error
Range of values for a sample
A test of significance
69
What is the LSRL?
Least Squares Regression Line
Largest Slope Regression Line
Lower Standard Regression Line
Logistic Standard Residual Line
70
unit 4: what is bias in sampling?
Using a large sample to improve result precision.
Including all data points from the population in the sample.
Error when the sample doesn't represent the population
Collecting data with equal selection chances for everyone.

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