Answer:
a) 
With:


b) 

c) 

d) 


Step-by-step explanation:
For this case we know the following propoertis for the random variable X

We select a sample size of n = 81
Part a
Since the sample size is large enough we can use the central limit distribution and the distribution for the sampel mean on this case would be:

With:


Part b
We want this probability:

We can use the z score formula given by:

And if we find the z score for 89 we got:


Part c

We can use the z score formula given by:

And if we find the z score for 75.65 we got:


Part d
We want this probability:

We find the z scores:



Answer:
A
Step-by-step explanation:
All triangles have 180 degrees, these set of measures do not add up to 180°. They add up to 181°, so it is the answer.
Answer:
mRP = 125°
mQS = 125°
mPQR = 235°
mRPQ = 305°
Step-by-step explanation:
Given that
Then:
- measure of arc RP, mRP = mROP = 125°
Given that
- ∠QOS and ∠ROP are vertical angles
Then:
- measure of arc QS, mQS = mROP = 125°
Given that
- ∠QOR and ∠SOP are vertical angles
Then:
Given that
- The addition of all central angles of a circle is 360°
Then:
mQOS + mROP + mQOR + mSOP = 360°
250° + 2mQOR = 360°
mQOR = (360°- 250°)/2
mQOR = mSOP = 55°
And (QOR and SOP are central angles):
- measure of arc QR, mQR = mQOR = 55°
- measure of arc SP, mSP = mSOP = 55°
Finally:
measure of arc PQR, mPQR = mQOR + mSOP + mQOS = 55° + 55° + 125° = 235°
measure of arc RPQ, mRPQ = mROP + mSOP + mQOS = 125° + 55° + 125° = 305°
The least amount of students mr Christensen has would be 5 because if he puts them in a group of 4 and one is left out that would equal to 5.