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
21/4 ÷ 14/9
21/4 × 9/14
189/56
3/3/8
<h3>Given :-</h3>
<h3>To Find :-</h3>
<h3>Solution :-</h3>
☼︎ <u>Radius of the Circle</u>;
<h3>Using Formula:</h3>

<u>Putting values in the formula;</u>









henceforth, the Radius of a circle is 14 cm ...!!