A2 Statistics Help
I need some help for this Sampling question please.
A random sample of 2n observations is taken of the random variable X~B(n,p) and p>0.5. The sample mean is denoted by Xbar. It is given that Var (Xbar) = 0.08 and E(Xbar) = 64.
a) Find the values of p and n.
I have used np = 64 and npq/2n = 0.08. My answers are n= 76 and p = 0.84. However, the textbook answers are n = 80 and p = 0.8.
A random sample of 2n observations is taken of the random variable X~B(n,p) and p>0.5. The sample mean is denoted by Xbar. It is given that Var (Xbar) = 0.08 and E(Xbar) = 64.
a) Find the values of p and n.
I have used np = 64 and npq/2n = 0.08. My answers are n= 76 and p = 0.84. However, the textbook answers are n = 80 and p = 0.8.
Original post by VTan
I need some help for this Sampling question please.
A random sample of 2n observations is taken of the random variable X~B(n,p) and p>0.5. The sample mean is denoted by Xbar. It is given that Var (Xbar) = 0.08 and E(Xbar) = 64.
a) Find the values of p and n.
I have used np = 64 and npq/2n = 0.08. My answers are n= 76 and p = 0.84. However, the textbook answers are n = 80 and p = 0.8.
A random sample of 2n observations is taken of the random variable X~B(n,p) and p>0.5. The sample mean is denoted by Xbar. It is given that Var (Xbar) = 0.08 and E(Xbar) = 64.
a) Find the values of p and n.
I have used np = 64 and npq/2n = 0.08. My answers are n= 76 and p = 0.84. However, the textbook answers are n = 80 and p = 0.8.
you can make two equations;
sub the info from first line and third line into (2) and solve for n (quadratic), only one value is valid due to restrictions on p
Quick Reply
Related discussions
- Further maths year 13
- Should I apply?
- A Level maths paper 3
- Cambridge Economics A-Level Help!!
- Mathematics AS re-sit
- How to get cheaper motorcycles insurance in London? Quoted 2.8k a year...
- A-level Maths
- Messed up CIE Math P3 and Physics P4.
- Cambridge Maths Grades
- Maths and archaeology
- Self studying further maths and maybe economics
- Low AS UMS, should I give up on propspects of Oxbridge?
- Maths or Maths and Economics degree
- Entering for an A2 exam as a private candidate
- Welcome to the A level forum!
- 2nd Alevel RETAKE ...
- Can't take further maths
- Psychology undergrad
- Is Undergrad Psychology hard?
- A*A*A* and A in AS FM, Economics at LSE or Cambridge?
Latest
Trending
Last reply 2 days ago
Did Cambridge maths students find maths and further maths a level very easy?Last reply 2 weeks ago
Edexcel A Level Mathematics Paper 2 unofficial mark scheme correct me if wrongMaths
71
Trending
Last reply 2 days ago
Did Cambridge maths students find maths and further maths a level very easy?Last reply 2 weeks ago
Edexcel A Level Mathematics Paper 2 unofficial mark scheme correct me if wrongMaths
71
