Question

Assume we are interested in the time it takes to complete a memory task for a dementia screening test. This distribution of this timing follows a normal distribution with a mean of 15 minutes and variance of 4 minutes.

1. What is the probability that a randomly selected participant’s time is longer than 7 minutes?

1-p<7

7-15/2 = 1-0.5 = 0.5

What is the probability that that same participant’s time is between 16 and 17 minutes?

2. What is the probability of that same participant’s time being exactly 13 minutes?
3. What is the probability of that same participant’s time being less than 12 minutes?

Answer 1

X is the random variable representing the time it takes to complete a memory task for a dementia screening test.

X is distributed normally with the following parameters.

a)

P(X > 7) = 0.9997

b) P(X = 13) = 0

The probability of a continuous random variable being equal to one particular value is always zero.

c)