BSIE Probability & Statistics 2

Question 1

A process has a defect rate of 2%. In a sample of 200 items, what is the expected number of defects?

Accepted Answer

4

Answer

Expected value = n × p = 200 × 0.02 = 4 defects.

Question 2

Which measure of central tendency is most resistant to outliers?

Accepted Answer

Median

Answer

The median is resistant to outliers because it depends only on the middle value(s), not the magnitude of extreme values.

Question 3

In a normal distribution, approximately what percentage of data falls within ±2 standard deviations of the mean?

Accepted Answer

95%

Answer

The empirical rule states that approximately 95% of data falls within ±2 standard deviations of the mean.

Question 4

Two events A and B are mutually exclusive. If P(A) = 0.3 and P(B) = 0.4, what is P(A ∪ B)?

Accepted Answer

0.70

Answer

For mutually exclusive events, P(A ∪ B) = P(A) + P(B) = 0.3 + 0.4 = 0.7.

Question 5

A production line fills bottles with a mean of 500 mL and standard deviation of 5 mL. What is the z-score for a bottle containing 512 mL?

Accepted Answer

2.4

Answer

z = (x − μ) / σ = (512 − 500) / 5 = 12 / 5 = 2.4.

BSIE - Bachelor of Science in Industrial Engineering Practice Test