Lesson 2.02g
2.02g Calculating mean and standard deviation Quiz: OCR Maths, Unit 12
20 questions
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Lesson 2.02g, Calculating mean and standard deviation: 20 multiple choice questions for the OCR Maths (H240), Unit 12: Data Presentation and Interpretation, written with Revision Ninja.
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The 20 questions
-
What property of a statistical dataset is measured by its standard deviation?
- Location
- Skewness
- Spread
- Size
-
Why are statistics calculated from a grouped frequency table described as estimates?
- Exact values unknown
- Frequencies are rounded
- Sample size varies
- Calculators use approximations
-
Which symbol on a standard graphical calculator represents population standard deviation?
- x̄
- Σx²
- σx
- sx
-
Which expression correctly calculates population variance from summary statistics?
- (Σx/n)² - x̄
- Σx²/n + x̄²
- √(Σx²/n - x̄²)
- (Σx²/n) - x̄²
-
A dataset has n = 25 and Σx = 150. What is the mean?
- 5
- 6
- 3750
- 6.25
-
A frequency distribution has total frequency 20 and Σfx = 140. What is the mean?
- 7
- 70
- 2800
- 0.14
-
A dataset has a variance of 16. What is its standard deviation?
- 4
- 2
- 256
- 8
-
For 10 data items, Σx² = 500 and the mean is 6. What is the variance?
- 44
- 50
- 16
- 14
-
Class A has a higher standard deviation in test scores than Class B. What does this indicate?
- Higher average score
- Lower average score
- More students tested
- More varied scores
-
Team A has a lower mean score than Team B. What does this mean?
- Lower average performance
- Fewer games played
- Less consistent scores
- Greater consistency
-
What is standard deviation relative to variance?
- Square
- Square root
- Half
- Double
-
If each value in a dataset is increased by 5, how does the mean change?
- Unchanged
- Multiplied by 5
- Increases by 25
- Increases by 5
-
If each value in a dataset is increased by 5, how does standard deviation change?
- Multiplied by 5
- Increases by 5
- Unchanged
- Increases by 25
-
Data x has mean 10 and standard deviation 2. If y = 3x + 1, what is the mean of y?
- 33
- 11
- 30
- 31
-
Data x has standard deviation 4. If y = 2x + 3, what is the standard deviation of y?
- 8
- 4
- 11
- 14
-
A set of 5 numbers has Σx² = 180 and x̄ = 4. What is the standard deviation?
- 2
- 20
- 36
- 4.47
-
In grouped data, what point in a class interval is used to estimate the mean?
- Lower boundary
- Class width
- Upper boundary
- Midpoint
-
Sample A (n = 10) has mean 4. Sample B (n = 10) has mean 8. What is the combined mean?
- 6
- 12
- 7
- 60
-
Using the mean ± 2 std dev rule, what is the upper outlier boundary if mean=50 and std dev=5?
- 60
- 62.5
- 70
- 55
-
What is the term for removing or correcting anomalous values from a raw dataset?
- Data cleaning
- Data grouping
- Data sampling
- Data coding
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