I need help with this. Both Standard Deviation and the Mean. Both have answer choices of Decrease, Increase, or stay the same.

Answer:
The mean will stay the same.
The standard deviation will decrease.
Step-by-step explanation:
For the 5 cards, she has received, the mean will be:
μ=(∑x)/n
=125/5
=25
The mean is 25 and the standard deviation is 10.
σ=10
If a new card is received with $25, then the sum will be $150
So the new mean will be:
μ'=(∑x)/n
=150/6
=25
And the new standard deviation will be:
σ'= 9.12
We can clearly see that
μ= μ'
and
σ> σ'
So the mean will remain the same and standard deviation will decrease. .