Facts About the Chi-Square Distribution Quiz
The question sheet
Reveal any answer as you study-
For the chi-square distribution, the population mean μ is equal to:
- df
- n
- zero
- df – 1
Reveal answer
Answer: df
Source evidence
PDF page 598: where df = degrees of freedom, which depends on how chi-square is being used. If you want to practice calculating chisquare probabilities then use df = n – –1. The degrees of freedom for the three major uses are calculated differently. 2 For the χ distribution, the population mean is μ = df, and the population standard deviation is . 2 The random variable is shown as χ , but it may be any uppercase letter. The random variable for a chi-square distribution with k degrees of freedom is the sum of k independent, squared standard normal variables is 2 2 2 2 χ = (Z1) + (Z2) + ... + (Zk) , where the following are true:
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The chi-square curve is described as:
- Uniform and flat
- Skewed to the left
- Symmetrical and bell-shaped
- Nonsymmetrical and skewed right
Reveal answer
Answer: Nonsymmetrical and skewed right
Source evidence
PDF page 598: • The curve is nonsymmetrical and skewed to the right.
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When df is greater than 90, the chi-square curve approximates the:
- Normal distribution
- Uniform distribution
- Student's t distribution
- Binomial distribution
Reveal answer
Answer: Normal distribution
Source evidence
PDF page 598: • When df > 90, the chi-square curve approximates the normal distribution. For X ~
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The mean μ of a chi-square distribution is located:
- Just to the right of the peak
- At the peak
- Far below zero
- Just to the left of the peak
Reveal answer
Answer: Just to the right of the peak
Source evidence
PDF page 598: • The mean, μ, is located just to the right of the peak.
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In the chi-square notation, df stands for:
- Degrees of freedom
- Distribution factor
- Difference formula
- Data frequency
Reveal answer
Answer: Degrees of freedom
Source evidence
PDF page 598: where df = degrees of freedom, which depends on how chi-square is being used. If you want to practice calculating chisquare probabilities then use df = n – –1. The degrees of freedom for the three major uses are calculated differently. 2 For the χ distribution, the population mean is μ = df, and the population standard deviation is . 2 The random variable is shown as χ , but it may be any uppercase letter. The random variable for a chi-square distribution with k degrees of freedom is the sum of k independent, squared standard normal variables is 2 2 2 2 χ = (Z1) + (Z2) + ... + (Zk) , where the following are true:
-
The number of degrees of freedom depends on:
- The sample mean
- The standard normal table
- The confidence level
- How chi-square is being used
Reveal answer
Answer: How chi-square is being used
Source evidence
PDF page 598: where df = degrees of freedom, which depends on how chi-square is being used. If you want to practice calculating chisquare probabilities then use df = n – –1. The degrees of freedom for the three major uses are calculated differently. 2 For the χ distribution, the population mean is μ = df, and the population standard deviation is . 2 The random variable is shown as χ , but it may be any uppercase letter. The random variable for a chi-square distribution with k degrees of freedom is the sum of k independent, squared standard normal variables is 2 2 2 2 χ = (Z1) + (Z2) + ... + (Zk) , where the following are true:
-
To practice calculating chi-square probabilities, use df equal to:
- 2n
- n
- n – 1
- n + 1
Reveal answer
Answer: n – 1
Source evidence
PDF page 598: where df = degrees of freedom, which depends on how chi-square is being used. If you want to practice calculating chisquare probabilities then use df = n – –1. The degrees of freedom for the three major uses are calculated differently. 2 For the χ distribution, the population mean is μ = df, and the population standard deviation is . 2 The random variable is shown as χ , but it may be any uppercase letter. The random variable for a chi-square distribution with k degrees of freedom is the sum of k independent, squared standard normal variables is 2 2 2 2 χ = (Z1) + (Z2) + ... + (Zk) , where the following are true:
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A chi-square random variable with k df is the sum of k independent, squared:
- Uniform variables
- Binomial variables
- Standard normal variables
- Sample means
Reveal answer
Answer: Standard normal variables
Source evidence
PDF page 598: where df = degrees of freedom, which depends on how chi-square is being used. If you want to practice calculating chisquare probabilities then use df = n – –1. The degrees of freedom for the three major uses are calculated differently. 2 For the χ distribution, the population mean is μ = df, and the population standard deviation is . 2 The random variable is shown as χ , but it may be any uppercase letter. The random variable for a chi-square distribution with k degrees of freedom is the sum of k independent, squared standard normal variables is 2 2 2 2 χ = (Z1) + (Z2) + ... + (Zk) , where the following are true:
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The random variable for chi-square is shown as χ², but it may be:
- Only lowercase letters
- A negative number
- Any uppercase letter
- Only the letter X
Reveal answer
Answer: Any uppercase letter
Source evidence
PDF page 598: where df = degrees of freedom, which depends on how chi-square is being used. If you want to practice calculating chisquare probabilities then use df = n – –1. The degrees of freedom for the three major uses are calculated differently. 2 For the χ distribution, the population mean is μ = df, and the population standard deviation is . 2 The random variable is shown as χ , but it may be any uppercase letter. The random variable for a chi-square distribution with k degrees of freedom is the sum of k independent, squared standard normal variables is 2 2 2 2 χ = (Z1) + (Z2) + ... + (Zk) , where the following are true:
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For X with df = 1,000, the standard deviation σ equals about:
- 1,000
- 44.7
- 90
- 100
Reveal answer
Answer: 44.7
Source evidence
PDF page 598: and the standard deviation, σ =
PDF page 598: = 44.7. Therefore, X ~ N(1,000, 44.7), approximately.
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For X with df = 1,000, X is approximately distributed as:
- N(0, 1)
- N(44.7, 1,000)
- N(90, 1,000)
- N(1,000, 44.7)
Reveal answer
Answer: N(1,000, 44.7)
Source evidence
PDF page 598: = 44.7. Therefore, X ~ N(1,000, 44.7), approximately.
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The degrees of freedom for the three major uses of chi-square are:
- Calculated differently
- Always zero
- Always n – 1
- Always the same
Reveal answer
Answer: Calculated differently
Source evidence
PDF page 598: where df = degrees of freedom, which depends on how chi-square is being used. If you want to practice calculating chisquare probabilities then use df = n – –1. The degrees of freedom for the three major uses are calculated differently. 2 For the χ distribution, the population mean is μ = df, and the population standard deviation is . 2 The random variable is shown as χ , but it may be any uppercase letter. The random variable for a chi-square distribution with k degrees of freedom is the sum of k independent, squared standard normal variables is 2 2 2 2 χ = (Z1) + (Z2) + ... + (Zk) , where the following are true:
Statistics
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