Answer:
21+4=25
Step-by-step explanation:
There is a probability of 77% that the mean of this sample is between 19.25 hours and 21.0 hours
Z score is used to determine by how many standard deviations the raw score is above or below the mean. The z score is given by:

Given that μ = 20, σ = 7, n = 125.
For x = 19.25:

From the normal distribution table, P(-1.20 < z < 0.62) = P(z < 0.62) - P(z < -1.2) = 0.8849 - 0.1151 = 0.7698 = 77%
There is a probability of 77% that the mean of this sample is between 19.25 hours and 21.0 hours
Find out more on z score at: brainly.com/question/25638875
Step-by-step explanation:
-3. 2
-2. 1
-7. 6
i did my best.
Answer:
I agree completely
Step-by-step explanation: