NBT NBT Statistics and Probability 5

Question 1

A scatter plot shows a strong negative correlation. Which statement best describes this relationship?

Accepted Answer

As x increases, y decreases

Answer

A negative correlation means that as one variable increases, the other decreases.

Question 2

In a normal distribution, approximately what percentage of data falls within one standard deviation of the mean?

Accepted Answer

68%

Answer

The empirical rule states that approximately 68% of data falls within one standard deviation of the mean.

Question 3

A bag has 6 red and 4 blue chips. Two chips are drawn without replacement. What is the probability both are red?

Accepted Answer

1/3

Answer

P(both red) = (6/10) × (5/9) = 30/90 = 1/3.

Question 4

Which of the following correctly describes a frequency histogram?

Accepted Answer

A bar graph where bars represent frequency of data intervals

Answer

A frequency histogram uses bars whose heights represent how often data values fall within each interval.

Question 5

The variance of a dataset measures:

Accepted Answer

The average squared deviation from the mean

Answer

Variance is the mean of the squared differences between each data point and the overall mean.

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