Question

The average amount of money spent on a Halloween costume is $50 with a standard deviation of $12.

a) What is the probability of choosing someone that spent less than $40?
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Answer 1

To find the probability of choosing someone who spent less than $40 on a Halloween costume, use the z-score formula. The probability is approximately 20.3%.

Step-by-step explanation:

To find the probability of choosing someone who spent less than $40 on a Halloween costume, we can use the z-score formula:

z = (x - μ) / σ

Where:
- z is the z-score
- x is the value we want to find the probability for (in this case, $40)
- μ is the mean value of the sample (which is $50)
- σ is the standard deviation (which is $12)

Substituting the values, we get:

z = (40 - 50) / 12 = -10 / 12 = -0.8333

Next, we can look up the corresponding probability from the z-table or use a calculator that provides the cumulative probability function. In this case, the probability of choosing someone who spent less than $40 is approximately 0.203, or 20.3%.