Answer:
Variance =10900.00
Standard deviation=104.50
Step by step Explanation:
Admissions Probability for 1100= 0.2
Admissions Probability for 1400=0.3
Admissions Probability for 1300 =0.5
To find the expected value, we will multiply each possibility by its probability and then add.
mean = 1100*0.2 + 1400*0.3 + 1300*0.5 = 1290
To find the variance, we will start by squaring each possibility and then multiplying it by its probability. We will then add these and subtract the mean squared.
E(X^2)=( 1100²*0.2)+ (1400²*0.3 )+ (1300²*0.5) = 1675000
Variance(X)=E(X²)- [E(X)]²
= 1675000 - (1290)²
=10900
Hence, the Variance(X)=10900
Then to calculate the standard variation , we will use the formular below,
standard variation (X)=√ var(X)= √10900
=104.5
Hence the standard variation=104.5
