OSAT Secondary Mathematics 3

Question 1

A data set has values: 4, 7, 7, 9, 11, 13. What is the median?

Accepted Answer

8

Answer

With 6 values, the median is the average of the 3rd and 4th values: (7 + 9) / 2 = 8.

Question 2

A bag contains 4 red, 3 blue, and 5 green marbles. What is the probability of drawing a blue marble?

Accepted Answer

1/4

Answer

Probability = 3 / (4 + 3 + 5) = 3/12 = 1/4.

Question 3

Which measure of central tendency is most affected by extreme values (outliers)?

Accepted Answer

Mean

Answer

The mean is most affected by outliers because every value in the data set contributes to its calculation.

Question 4

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 5

A scatter plot shows that as one variable increases, the other also increases. What type of correlation is this?

Accepted Answer

Positive correlation

Answer

When both variables increase together, they exhibit a positive correlation.

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