# Answers to the checkpoints of chapter 4

Checkpoint 1

• Subjective probability.
• Relative probability.
• Probability of knowing.
• Probability of drawing a king: 4/52, probability of drawing a king of diamonds: 1/52.

Checkpoint 2

• 93%
• 0.0049
• 0.0651
• Three emergency calls are not independent; they probably concern the same incident. They are too close together and from the same suburb.

Checkpoint 3

• Both indicate the number of possible variations of a number of elements from a set. If it is a permutation, the order is taken into account. If it is a combination, it is not.
• Number of combinations: 6 choose 2 = 15
Number of permutations 6*5 = 30

Checkpoint 4

• It is a probability distribution with replacement, whereby the probabilities occur independently of each other.
• Hypergeometric = with replacement; binomial = without replacement.
• He can check this by doing a hypergeometric probability experiment.
• He would now use a binomial probability experiment.
• The expected value is the expected result of an experiment if the result is not known.

Checkpoint 5

• A normal probability experiment has a continuous distribution; hypergeometric and binomial probability distributions have a discrete distribution.
• When you do a transformation, you standardize the values according to the z scale and make it possible to compare variables with different scales.
• In both distributions, the figure is bell shaped, and in both distributions the empirical rule applies (as does Chebyshev’s rule). The difference is that in a standard normal distribution the mean is “0” and the standard deviation it is “1” because it has been transformed according to the z distribution.

Checkpoint 6

Repeatability as a condition for the reliability of results.

Checkpoint 7

• The p value represents the probability value: the probability of a certain event, given some basic data.
• The difference between the right and left probability value has to do with the area where the z value is located: right or left of the center of the distribution.
• The probability value is slightly more than 5%; the chance that the manufacturer would adjust his machines at this value is small.

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