The Dow Jones Industrial Avera
The Dow Jones Industrial Average has had a mean gain of 432 pearyear with a standard deviation of 722. A random sample of 40 yearsis selected. What is the probability that the mean gain for thesample was between 250 and 500?
0.669
0.137
0.331
0.863
Answer:
Solution :
Given that,
mean = 
= 432
standard deviation = 
= 722
n = 40
= 432
= (/
P ( 250 < x < 500 )
P ( 250 – 432 / 114.1582 ) < ( – / ) < ( 500 – 432 / 114.1582 )
P ( – 182 / 114.1582 < z < 68 / 114.1582 )
P ( -1.594 < z < 0.596 )
P ( z < 0.596 ) – P ( z < -1.594 )
Using z table
= 0.7244 – 0.0555
= 0.6689
Probability = 0.669
Option 0.669 is correct.
"Our Prices Start at $11.99. As Our First Client, Use Coupon Code GET15 to claim 15% Discount This Month!!"
