Answer:
The sample mean is
min.
The sample standard deviation is
min.
Step-by-step explanation:
We have the following data set:

The mean of a data set is commonly known as the average. You find the mean by taking the sum of all the data values and dividing that sum by the total number of data values.
The formula for the mean of a sample is

where,
is the number of values in the data set.

The standard deviation measures how close the set of data is to the mean value of the data set. If data set have high standard deviation than the values are spread out very much. If data set have small standard deviation the data points are very close to the mean.
To find standard deviation we use the following formula

The mean of a sample is
.
Create the below table.
Find the sum of numbers in the last column to get.


Answer:
126 hrs
Step-by-step explanation:
-Given the school year has 180 days and the non-working student spends 42 minutes more than the working student.
-The total time during the school year is calculated as;

We convert our calculated time in hour(1hr=60 minutes):

Hence, the average non-working spends an average of 126 hrs that the working student.
I think you mean:
A parking lot is 100 yards long. What is the length of 3/4 of the parking lot?
3/4 * 100 Mathematical Expression.
3/1 * 25 Simplify.
75 Multiply.
Final Answer: 75 yards long