Using it's concept, the standard deviation for the given data-set is of 8.22.
<h3>What are the mean and the standard deviation of a data-set?</h3>
- The mean of a data-set is given by the <u>sum of all values in the data-set, divided by the number of values</u>.
- The standard deviation of a data-set is given by the square root of the <u>sum of the differences squared between each observation and the mean, divided by the number of values</u>.
The mean for this problem is:
M = (17 + 26 + 28 + 9 + 30 + 29 + 6 + 21 + 23)/9 = 21
Hence the standard deviation is:

More can be learned about the standard deviation of a data-set at brainly.com/question/12180602
#SPJ1
Answer:
45 km/h
Step-by-step explanation:
In the first part of the trip, he already covered 30 km so we can subtract that from the total distance
45 - 30 = 15
This means he has 15 km to go
He also took an hour, or 60 minutes, to get to school. We subtract the time spent of the first part and time spent talking to a friend from the 60 minutes
60 - 35 = 25
25 - 5 = 20
He took 20 minutes to cover the second part of the journey
Speed = distance/time
15/20 = 0.75
He covered 0.75 km per MINUTE
to find it in km/h, we just multiply the number by 60
0.75 x 60 = 45
He sold about <span>80% of his tickets</span>
Answer:
%176
Step-by-step explanation:
1/4n x 1/2 = 22
Solve the equation and get 176.